Human Diseases
Q241MediumBPSC Prelims
Tuberculosis (TB) is caused by which pathogen?
AMycobacterium tuberculosis (bacterium)
BMycobacterium tuberculosis virus
CPlasmodium tuberculosis (protozoan)
DAspergillus tuberculosis (fungus)
Show Answer
✔ A — Mycobacterium tuberculosis (bacterium)
Tuberculosis (TB): caused by Mycobacterium tuberculosis (Koch's bacillus) — a slow-growing, aerobic, rod-shaped bacterium.
- Discovered by Robert Koch (1882) → Nobel Prize 1905
- Transmitted: airborne droplets from coughing, sneezing of infected person
- Primarily affects lungs (pulmonary TB) but can affect any organ
- Diagnosis: Mantoux test (tuberculin skin test), Sputum smear (AFB), GeneXpert (rapid molecular test)
- Treatment: Directly Observed Treatment Short-course (DOTS) — standard 6-month regimen: HRZE (Isoniazid, Rifampicin, Pyrazinamide, Ethambutol)
- Drug-resistant TB: MDR-TB (Multi-Drug Resistant) and XDR-TB (Extensively Drug-Resistant) — serious public health threat
*Why B is wrong:* Mycobacterium tuberculosis is a BACTERIUM, not a virus.
*Why C is wrong:* Plasmodium causes malaria, not TB.
*Why D is wrong:* Aspergillus is a fungus causing aspergillosis — not TB.
- Discovered by Robert Koch (1882) → Nobel Prize 1905
- Transmitted: airborne droplets from coughing, sneezing of infected person
- Primarily affects lungs (pulmonary TB) but can affect any organ
- Diagnosis: Mantoux test (tuberculin skin test), Sputum smear (AFB), GeneXpert (rapid molecular test)
- Treatment: Directly Observed Treatment Short-course (DOTS) — standard 6-month regimen: HRZE (Isoniazid, Rifampicin, Pyrazinamide, Ethambutol)
- Drug-resistant TB: MDR-TB (Multi-Drug Resistant) and XDR-TB (Extensively Drug-Resistant) — serious public health threat
*Why B is wrong:* Mycobacterium tuberculosis is a BACTERIUM, not a virus.
*Why C is wrong:* Plasmodium causes malaria, not TB.
*Why D is wrong:* Aspergillus is a fungus causing aspergillosis — not TB.
Q242MediumBPSC Prelims
Dengue fever is transmitted by:
AFemale Anopheles mosquito
BMale Aedes aegypti mosquito
CFemale Aedes aegypti mosquito
DSandfly (Phlebotomus)
Show Answer
✔ C — Female Aedes aegypti mosquito
Dengue fever: caused by Dengue virus (DENV) — 4 serotypes (DENV-1 to DENV-4); Family Flaviviridae.
Vector: Female Aedes aegypti mosquito (primary vector); also Aedes albopictus (tiger mosquito).
Aedes aegypti features:
- Bites during DAY (especially dawn and dusk) — unlike Anopheles which bites at night
- Breeds in clean, stagnant water containers (flower pots, water tanks, tyres)
- Black and white striped legs (distinctive appearance)
Dengue symptoms: sudden high fever, severe headache, pain behind eyes, joint and muscle pain ("breakbone fever"), skin rash.
Warning signs for severe dengue: abdominal pain, persistent vomiting, bleeding, rapid breathing, fatigue.
Dengue Haemorrhagic Fever (DHF): thrombocytopenia (platelet count drops below 1 lakh/μL) → bleeding.
*Why A is wrong:* Female Anopheles transmits MALARIA — not dengue.
*Why B is wrong:* MALE mosquitoes don't bite — they feed on plant nectar.
*Why D is wrong:* Sandfly (Phlebotomus) transmits Leishmaniasis/Kala-Azar (Leishmania donovani) — not dengue.
Vector: Female Aedes aegypti mosquito (primary vector); also Aedes albopictus (tiger mosquito).
Aedes aegypti features:
- Bites during DAY (especially dawn and dusk) — unlike Anopheles which bites at night
- Breeds in clean, stagnant water containers (flower pots, water tanks, tyres)
- Black and white striped legs (distinctive appearance)
Dengue symptoms: sudden high fever, severe headache, pain behind eyes, joint and muscle pain ("breakbone fever"), skin rash.
Warning signs for severe dengue: abdominal pain, persistent vomiting, bleeding, rapid breathing, fatigue.
Dengue Haemorrhagic Fever (DHF): thrombocytopenia (platelet count drops below 1 lakh/μL) → bleeding.
*Why A is wrong:* Female Anopheles transmits MALARIA — not dengue.
*Why B is wrong:* MALE mosquitoes don't bite — they feed on plant nectar.
*Why D is wrong:* Sandfly (Phlebotomus) transmits Leishmaniasis/Kala-Azar (Leishmania donovani) — not dengue.
Q243HardBPSC Prelims
Typhoid fever is caused by Salmonella typhi and is primarily transmitted through:
APerson-to-person direct contact (touching)
BAirborne droplets from infected persons
CContaminated food and water (fecal-oral route)
DMosquito bites
Show Answer
✔ C — Contaminated food and water (fecal-oral route)
Typhoid fever: caused by Salmonella typhi (bacterium); transmitted via fecal-oral route — contaminated food or water.
- S. typhi ingested → survives stomach acid → infects small intestinal mucosa → enters bloodstream (bacteremia)
- Incubation: 1-3 weeks
- Symptoms: sustained high fever (step-ladder fever pattern), abdominal pain, rose spots on skin, splenomegaly, bradycardia (slow heart rate despite fever = Faget's sign)
- Diagnosis: Widal test (antibody detection), Blood culture (gold standard)
- Treatment: Fluoroquinolones (ciprofloxacin) or Ceftriaxone; chloramphenicol historically
- Prevention: Clean water, proper sanitation, hand washing, Typhoid Vi polysaccharide vaccine
*Why A is wrong:* Typhoid spreads through contaminated FOOD/WATER, not direct touch.
*Why B is wrong:* Airborne spread = tuberculosis, measles, COVID-19 — not typhoid.
*Why D is wrong:* Mosquito-borne diseases include malaria, dengue, chikungunya — not typhoid.
- S. typhi ingested → survives stomach acid → infects small intestinal mucosa → enters bloodstream (bacteremia)
- Incubation: 1-3 weeks
- Symptoms: sustained high fever (step-ladder fever pattern), abdominal pain, rose spots on skin, splenomegaly, bradycardia (slow heart rate despite fever = Faget's sign)
- Diagnosis: Widal test (antibody detection), Blood culture (gold standard)
- Treatment: Fluoroquinolones (ciprofloxacin) or Ceftriaxone; chloramphenicol historically
- Prevention: Clean water, proper sanitation, hand washing, Typhoid Vi polysaccharide vaccine
*Why A is wrong:* Typhoid spreads through contaminated FOOD/WATER, not direct touch.
*Why B is wrong:* Airborne spread = tuberculosis, measles, COVID-19 — not typhoid.
*Why D is wrong:* Mosquito-borne diseases include malaria, dengue, chikungunya — not typhoid.
Q244MediumBPSC Prelims
Kala-azar (Visceral Leishmaniasis) is caused by which organism and is endemic in which Bihar districts?
APlasmodium vivax — Gaya, Nalanda districts
BLeishmania donovani (protozoan) — Muzaffarpur, Saran, Sitamarhi, Champaran districts
CWuchereria bancrofti (helminth) — Patna, Bhagalpur districts
DMycobacterium leprae (bacterium) — Vaishali, Darbhanga districts
Show Answer
✔ B — Leishmania donovani (protozoan) — Muzaffarpur, Saran, Sitamarhi, Champaran districts
Kala-azar (Visceral Leishmaniasis):
- Causative agent: Leishmania donovani (protozoan parasite)
- Vector: Phlebotomus argentipes (sandfly, female bites at night in dark corners)
- Bihar significance: India accounts for ~50% of global Kala-azar burden; Bihar has ~90% of India's cases
Endemic districts: Muzaffarpur, Saran (Chhapra), Sitamarhi, East/West Champaran, Vaishali, Darbhanga — Terai belt along Nepal border.
Symptoms: prolonged fever (>2 weeks), weight loss, splenomegaly (massive spleen), hepatomegaly, anaemia, darkening of skin (kala-azar = "black fever" in Hindi).
Treatment: Amphotericin B (drug of choice), Miltefosine (oral drug).
National Kala-azar Elimination Programme: target to eliminate (<1 case/10,000 population) by 2023 (extended).
*Why A is wrong:* Plasmodium vivax causes malaria — different vector, different district distribution.
*Why C is wrong:* Wuchereria bancrofti causes lymphatic filariasis (elephantiasis) — transmitted by Culex mosquito.
*Why D is wrong:* Mycobacterium leprae causes leprosy — contact, not vector-borne.
- Causative agent: Leishmania donovani (protozoan parasite)
- Vector: Phlebotomus argentipes (sandfly, female bites at night in dark corners)
- Bihar significance: India accounts for ~50% of global Kala-azar burden; Bihar has ~90% of India's cases
Endemic districts: Muzaffarpur, Saran (Chhapra), Sitamarhi, East/West Champaran, Vaishali, Darbhanga — Terai belt along Nepal border.
Symptoms: prolonged fever (>2 weeks), weight loss, splenomegaly (massive spleen), hepatomegaly, anaemia, darkening of skin (kala-azar = "black fever" in Hindi).
Treatment: Amphotericin B (drug of choice), Miltefosine (oral drug).
National Kala-azar Elimination Programme: target to eliminate (<1 case/10,000 population) by 2023 (extended).
*Why A is wrong:* Plasmodium vivax causes malaria — different vector, different district distribution.
*Why C is wrong:* Wuchereria bancrofti causes lymphatic filariasis (elephantiasis) — transmitted by Culex mosquito.
*Why D is wrong:* Mycobacterium leprae causes leprosy — contact, not vector-borne.
Q245HardBPSC Prelims
Cancer cells differ from normal cells primarily because:
ACancer cells have different DNA from normal cells in the same person
BCancer cells undergo uncontrolled cell division due to mutations in proto-oncogenes and tumour suppressor genes
CCancer cells always come from external viral infections
DCancer cells are larger than normal cells and can be seen with the naked eye
Show Answer
✔ B — Cancer cells undergo uncontrolled cell division due to mutations in proto-oncogenes and tumour suppressor genes
Cancer = uncontrolled cell proliferation due to genetic mutations:
Proto-oncogenes → mutate to oncogenes: drive unlimited cell division (accelerator stuck on).
Tumour suppressor genes (p53, Rb, BRCA1/2): normally brake cell division → inactivating mutations remove the brake.
Key hallmarks of cancer cells (Hanahan & Weinberg):
1. Self-sufficiency in growth signals
2. Insensitivity to growth-inhibitory signals
3. Evasion of apoptosis
4. Limitless replication potential
5. Sustained angiogenesis
6. Tissue invasion and metastasis
Types: Carcinoma (epithelial cells), Sarcoma (connective tissue), Leukaemia (blood cells), Lymphoma (lymphoid tissue), Glioma (brain).
*Why A is wrong:* Cancer cells have the SAME basic DNA as normal cells (they descend from them) but with ACQUIRED mutations.
*Why C is wrong:* While some cancers are virus-linked (HPV → cervical cancer; HBV/HCV → liver cancer), many cancers are not viral.
*Why D is wrong:* Cancer cells are NOT larger than normal cells — they appear similar microscopically, distinguished by abnormal nuclear patterns (dysplasia).
Proto-oncogenes → mutate to oncogenes: drive unlimited cell division (accelerator stuck on).
Tumour suppressor genes (p53, Rb, BRCA1/2): normally brake cell division → inactivating mutations remove the brake.
Key hallmarks of cancer cells (Hanahan & Weinberg):
1. Self-sufficiency in growth signals
2. Insensitivity to growth-inhibitory signals
3. Evasion of apoptosis
4. Limitless replication potential
5. Sustained angiogenesis
6. Tissue invasion and metastasis
Types: Carcinoma (epithelial cells), Sarcoma (connective tissue), Leukaemia (blood cells), Lymphoma (lymphoid tissue), Glioma (brain).
*Why A is wrong:* Cancer cells have the SAME basic DNA as normal cells (they descend from them) but with ACQUIRED mutations.
*Why C is wrong:* While some cancers are virus-linked (HPV → cervical cancer; HBV/HCV → liver cancer), many cancers are not viral.
*Why D is wrong:* Cancer cells are NOT larger than normal cells — they appear similar microscopically, distinguished by abnormal nuclear patterns (dysplasia).
Q255MediumBPSC Prelims
Cholera is caused by Vibrio cholerae and leads to severe dehydration because:
AIt destroys red blood cells and causes internal bleeding
BThe bacteria release a toxin that activates chloride channels in intestinal cells → massive secretion of water and electrolytes into the gut → watery diarrhoea
CIt infects the kidneys and prevents urine production
DIt blocks the intestine, preventing any fluid absorption
Show Answer
✔ B — The bacteria release a toxin that activates chloride channels in intestinal cells → massive secretion of water and electrolytes into the gut → watery diarrhoea
Cholera: caused by Vibrio cholerae (Gram-negative, comma-shaped bacterium).
- Transmitted: contaminated water and food (fecal-oral route)
- Incubation: hours to 5 days
Mechanism: Cholera toxin (CT) binds to intestinal cells → activates adenylyl cyclase → increases cAMP → opens Cl⁻ channels (CFTR) → massive Cl⁻, Na⁺, and WATER secretion into lumen → rice-water stools (up to 20 litres/day!!)
Treatment: Oral Rehydration Solution (ORS) — glucose-electrolyte solution exploits Na⁺/glucose cotransporter that is NOT affected by cholera toxin → rapidly replaces lost fluid. Only severe cases need IV fluid.
Nobel Prize: cholera treatment with ORS reduced cholera mortality from 50-60% to <1%. ORS is considered "the greatest medical advance of the 20th century."
*Why A is wrong:* Cholera doesn't destroy RBCs (haemolysis occurs in other conditions like blackwater fever in malaria).
*Why C is wrong:* Kidneys reduce urine output as a RESPONSE to dehydration — the bacteria don't directly infect kidneys.
*Why D is wrong:* Cholera doesn't block the intestine — it overstimulates secretion.
- Transmitted: contaminated water and food (fecal-oral route)
- Incubation: hours to 5 days
Mechanism: Cholera toxin (CT) binds to intestinal cells → activates adenylyl cyclase → increases cAMP → opens Cl⁻ channels (CFTR) → massive Cl⁻, Na⁺, and WATER secretion into lumen → rice-water stools (up to 20 litres/day!!)
Treatment: Oral Rehydration Solution (ORS) — glucose-electrolyte solution exploits Na⁺/glucose cotransporter that is NOT affected by cholera toxin → rapidly replaces lost fluid. Only severe cases need IV fluid.
Nobel Prize: cholera treatment with ORS reduced cholera mortality from 50-60% to <1%. ORS is considered "the greatest medical advance of the 20th century."
*Why A is wrong:* Cholera doesn't destroy RBCs (haemolysis occurs in other conditions like blackwater fever in malaria).
*Why C is wrong:* Kidneys reduce urine output as a RESPONSE to dehydration — the bacteria don't directly infect kidneys.
*Why D is wrong:* Cholera doesn't block the intestine — it overstimulates secretion.
Q256MediumBPSC Prelims
Which of the following is a viral disease?
ATuberculosis
BCholera
CRabies
DMalaria
Show Answer
✔ C — Rabies
Rabies: caused by Rabies virus (Lyssavirus genus, Family Rhabdoviridae).
- Transmission: bite of infected animal (dog most common in India — 96% of cases); also cats, monkeys, bats
- Incubation period: 1 week to 1 year (usually 1-3 months) — depends on bite location (farther from brain = longer incubation)
- Virus travels from wound along peripheral nerves to brain (retrograde axonal transport)
- Symptoms: hydrophobia (fear of water — pharyngeal spasms when swallowing), aerophobia, aggression, hypersalivation, paralysis, coma, death (near 100% fatal once symptoms appear)
- Prevention: Pre-Exposure Prophylaxis (PrEP) for vets, dog handlers; Post-Exposure Prophylaxis (PEP) — wound washing + rabies vaccine ± Rabies Immunoglobulin (RIG)
Classification of diseases:
- Viral: Rabies, COVID-19, Dengue, Hepatitis B/C, HIV/AIDS, Influenza, Measles, Polio
- Bacterial: TB, Cholera, Typhoid, Leprosy, Plague
- Protozoal: Malaria, Kala-azar, Amoebiasis, Giardiasis
- Helminthic: Filariasis, Ascariasis, Tapeworm
*Why A is wrong:* TB = bacterial (Mycobacterium tuberculosis).
*Why B is wrong:* Cholera = bacterial (Vibrio cholerae).
*Why D is wrong:* Malaria = protozoal (Plasmodium species).
- Transmission: bite of infected animal (dog most common in India — 96% of cases); also cats, monkeys, bats
- Incubation period: 1 week to 1 year (usually 1-3 months) — depends on bite location (farther from brain = longer incubation)
- Virus travels from wound along peripheral nerves to brain (retrograde axonal transport)
- Symptoms: hydrophobia (fear of water — pharyngeal spasms when swallowing), aerophobia, aggression, hypersalivation, paralysis, coma, death (near 100% fatal once symptoms appear)
- Prevention: Pre-Exposure Prophylaxis (PrEP) for vets, dog handlers; Post-Exposure Prophylaxis (PEP) — wound washing + rabies vaccine ± Rabies Immunoglobulin (RIG)
Classification of diseases:
- Viral: Rabies, COVID-19, Dengue, Hepatitis B/C, HIV/AIDS, Influenza, Measles, Polio
- Bacterial: TB, Cholera, Typhoid, Leprosy, Plague
- Protozoal: Malaria, Kala-azar, Amoebiasis, Giardiasis
- Helminthic: Filariasis, Ascariasis, Tapeworm
*Why A is wrong:* TB = bacterial (Mycobacterium tuberculosis).
*Why B is wrong:* Cholera = bacterial (Vibrio cholerae).
*Why D is wrong:* Malaria = protozoal (Plasmodium species).
Q257MediumBPSC Prelims
Leprosy (Hansen's disease) is caused by which organism?
ALeptomonas organisms (protozoan)
BMycobacterium leprae (bacterium) — a slow-growing organism
CLeishmania leprosalis (protozoan)
DPlasmodium leprae (protozoan)
Show Answer
✔ B — Mycobacterium leprae (bacterium) — a slow-growing organism
Leprosy (Hansen's Disease): caused by Mycobacterium leprae — discovered by Armauer Hansen (1873).
- VERY slow-growing bacterium (doubling time: 12-14 days — slowest of all known bacteria)
- Cannot be cultured in vitro (only in armadillos and mouse footpads)
- Transmission: droplets from nasal secretions; prolonged close contact
- Affects: skin, peripheral nerves, upper respiratory tract, eyes
Types:
- Tuberculoid leprosy (TT): strong immune response; few bacteria; hypopigmented patches with loss of sensation
- Lepromatous leprosy (LL): weak immune response; many bacteria; nodular skin lesions (lepromatous nodes), lionface appearance
- Borderline: between the two extremes
Treatment: Multi-Drug Therapy (MDT) — Dapsone + Rifampicin + Clofazimine (12 months for lepromatous; 6 months for tuberculoid). India declared leprosy eliminated (<1 case/10,000) nationally in 2005; some states including Bihar still have high prevalence.
*Why A, C, D:* All incorrect — leprosy is BACTERIAL, not protozoal.
- VERY slow-growing bacterium (doubling time: 12-14 days — slowest of all known bacteria)
- Cannot be cultured in vitro (only in armadillos and mouse footpads)
- Transmission: droplets from nasal secretions; prolonged close contact
- Affects: skin, peripheral nerves, upper respiratory tract, eyes
Types:
- Tuberculoid leprosy (TT): strong immune response; few bacteria; hypopigmented patches with loss of sensation
- Lepromatous leprosy (LL): weak immune response; many bacteria; nodular skin lesions (lepromatous nodes), lionface appearance
- Borderline: between the two extremes
Treatment: Multi-Drug Therapy (MDT) — Dapsone + Rifampicin + Clofazimine (12 months for lepromatous; 6 months for tuberculoid). India declared leprosy eliminated (<1 case/10,000) nationally in 2005; some states including Bihar still have high prevalence.
*Why A, C, D:* All incorrect — leprosy is BACTERIAL, not protozoal.
Biotechnology
Q246MediumBPSC Prelims
Polymerase Chain Reaction (PCR) is a technique used to:
ASequence the entire human genome
BAmplify (make millions of copies of) specific DNA segments in vitro
CCreate recombinant DNA by inserting genes into vectors
DTranslate mRNA into proteins in a test tube
Show Answer
✔ B — Amplify (make millions of copies of) specific DNA segments in vitro
PCR (Polymerase Chain Reaction): invented by Kary Mullis (1983, Nobel Prize 1993).
Purpose: Amplify a specific DNA sequence — from nanograms to micrograms (>1 billion copies).
PCR steps (thermal cycling):
1. Denaturation (94-98°C): DNA double helix separates into single strands
2. Annealing (50-65°C): Primers bind to complementary sequences flanking target region
3. Extension (72°C): Taq polymerase synthesises new DNA strand from each primer
Key components: target DNA, specific primers (short oligonucleotides), Taq polymerase (heat-stable enzyme from Thermus aquaticus), dNTPs (building blocks), MgCl₂.
Applications:
- COVID-19 diagnosis (RT-PCR = reverse transcription PCR — detects viral RNA)
- Forensic DNA fingerprinting
- Paternity testing
- Genetic disease diagnosis (prenatal)
- Detection of bacterial/viral infections
*Why A is wrong:* DNA sequencing (Sanger method, Next Generation Sequencing) is a separate technique.
*Why C is wrong:* Recombinant DNA technology uses restriction enzymes + DNA ligase to insert genes into vectors.
*Why D is wrong:* In vitro translation uses ribosomes, tRNA, mRNA — not PCR.
Purpose: Amplify a specific DNA sequence — from nanograms to micrograms (>1 billion copies).
PCR steps (thermal cycling):
1. Denaturation (94-98°C): DNA double helix separates into single strands
2. Annealing (50-65°C): Primers bind to complementary sequences flanking target region
3. Extension (72°C): Taq polymerase synthesises new DNA strand from each primer
Key components: target DNA, specific primers (short oligonucleotides), Taq polymerase (heat-stable enzyme from Thermus aquaticus), dNTPs (building blocks), MgCl₂.
Applications:
- COVID-19 diagnosis (RT-PCR = reverse transcription PCR — detects viral RNA)
- Forensic DNA fingerprinting
- Paternity testing
- Genetic disease diagnosis (prenatal)
- Detection of bacterial/viral infections
*Why A is wrong:* DNA sequencing (Sanger method, Next Generation Sequencing) is a separate technique.
*Why C is wrong:* Recombinant DNA technology uses restriction enzymes + DNA ligase to insert genes into vectors.
*Why D is wrong:* In vitro translation uses ribosomes, tRNA, mRNA — not PCR.
Q247MediumBPSC Prelims
Genetically Modified (GM) crops are developed by:
ATraditional crossbreeding of related plant varieties
BInserting specific foreign genes into a plant's genome to impart desired traits
CGrowing crops under artificial light conditions
DTreating seeds with chemical mutagenic agents
Show Answer
✔ B — Inserting specific foreign genes into a plant's genome to impart desired traits
GM (Genetically Modified) crops / Transgenic crops: organisms whose genome has been altered by inserting ONE OR MORE genes from another organism (or engineered synthetic gene).
Process:
1. Identify and isolate the gene of interest (e.g., Bt toxin gene from Bacillus thuringiensis)
2. Clone into a vector (Ti plasmid from Agrobacterium tumefaciens, or gene gun)
3. Transform plant cells → regenerate whole plant
4. Select and test transformed plants
Examples:
- Bt cotton: Bt toxin gene → produces insecticidal crystal protein → kills cotton bollworm → no pesticide needed → India's 95% cotton area is Bt cotton
- Bt brinjal: Bt toxin → insect resistance; controversially approved in Bangladesh
- Golden Rice: β-carotene genes → vitamin A precursor in rice endosperm → prevents vitamin A deficiency
- Herbicide-resistant soybean (Roundup Ready): glyphosate resistance
*Why A is wrong:* Traditional crossbreeding = hybridisation within same/related species — no foreign gene insertion.
*Why C is wrong:* Artificial light growing = hydroponics/vertical farming — not genetic modification.
*Why D is wrong:* Chemical mutagenesis = random mutations (mutation breeding) — not targeted gene insertion.
Process:
1. Identify and isolate the gene of interest (e.g., Bt toxin gene from Bacillus thuringiensis)
2. Clone into a vector (Ti plasmid from Agrobacterium tumefaciens, or gene gun)
3. Transform plant cells → regenerate whole plant
4. Select and test transformed plants
Examples:
- Bt cotton: Bt toxin gene → produces insecticidal crystal protein → kills cotton bollworm → no pesticide needed → India's 95% cotton area is Bt cotton
- Bt brinjal: Bt toxin → insect resistance; controversially approved in Bangladesh
- Golden Rice: β-carotene genes → vitamin A precursor in rice endosperm → prevents vitamin A deficiency
- Herbicide-resistant soybean (Roundup Ready): glyphosate resistance
*Why A is wrong:* Traditional crossbreeding = hybridisation within same/related species — no foreign gene insertion.
*Why C is wrong:* Artificial light growing = hydroponics/vertical farming — not genetic modification.
*Why D is wrong:* Chemical mutagenesis = random mutations (mutation breeding) — not targeted gene insertion.
Q248HardBPSC Prelims
CRISPR-Cas9 is a revolutionary genome-editing tool. "CRISPR" stands for:
AClustered Regularly Interspaced Short Palindromic Repeats
BContinuous Recombination Involving Specific Protein Repeats
CCloned Retroviral Integration of Specific Protein Repeats
DCircular Regulated Intron-Specific Protein Ribozymes
Show Answer
✔ A — Clustered Regularly Interspaced Short Palindromic Repeats
CRISPR-Cas9: genome editing tool developed by Jennifer Doudna & Emmanuelle Charpentier (Nobel Prize in Chemistry 2020).
Full form: Clustered Regularly Interspaced Short Palindromic Repeats
- These are repetitive DNA sequences found in bacterial genomes — part of the bacterial immune system (adaptive immunity against phages)
How CRISPR-Cas9 works:
1. Guide RNA (gRNA): designed to match the target DNA sequence
2. Cas9 protein: molecular scissors — cuts DNA at the gRNA-specified location
3. DNA repair: cell repairs cut via NHEJ (non-homologous end joining — gene knockout) or HDR (homology-directed repair — gene correction/insertion)
Applications:
- Gene therapy (sickle cell disease cure: Casgevy approved 2023 — first CRISPR therapy)
- Disease model creation (cancer research)
- Agriculture (disease-resistant crops without transgenes)
- Diagnostic tools (SHERLOCK system detects COVID-19)
*Why B, C, D:* All incorrect expansions — not the actual acronym.
Full form: Clustered Regularly Interspaced Short Palindromic Repeats
- These are repetitive DNA sequences found in bacterial genomes — part of the bacterial immune system (adaptive immunity against phages)
How CRISPR-Cas9 works:
1. Guide RNA (gRNA): designed to match the target DNA sequence
2. Cas9 protein: molecular scissors — cuts DNA at the gRNA-specified location
3. DNA repair: cell repairs cut via NHEJ (non-homologous end joining — gene knockout) or HDR (homology-directed repair — gene correction/insertion)
Applications:
- Gene therapy (sickle cell disease cure: Casgevy approved 2023 — first CRISPR therapy)
- Disease model creation (cancer research)
- Agriculture (disease-resistant crops without transgenes)
- Diagnostic tools (SHERLOCK system detects COVID-19)
*Why B, C, D:* All incorrect expansions — not the actual acronym.
Q249MediumBPSC Prelims
The technique of Recombinant DNA Technology uses restriction enzymes because:
ARestriction enzymes amplify DNA in a chain reaction
BRestriction enzymes cut DNA at specific recognition sequences, producing fragments for gene cloning
CRestriction enzymes synthesise new DNA from RNA templates
DRestriction enzymes help in protein synthesis
Show Answer
✔ B — Restriction enzymes cut DNA at specific recognition sequences, producing fragments for gene cloning
Restriction Enzymes (Restriction Endonucleases): molecular scissors that cut DNA at specific, short palindromic sequences called restriction sites.
- Discovered by Werner Arber, Daniel Nathans, Hamilton Smith (Nobel Prize 1978)
- Example: EcoRI cuts at GAATTC sequence → produces sticky ends (5'-AATT-3')
- Sticky ends: complementary overhangs that allow DNA from different organisms to hybridise (join)
Recombinant DNA technology process:
1. Restriction enzyme cuts both GENE OF INTEREST and VECTOR (plasmid) at same recognition site
2. DNA ligase joins the gene into the vector → RECOMBINANT DNA
3. Vector introduced into host cell (E. coli, yeast) → host replicates → gene expressed → protein produced
Applications:
- Insulin production (human insulin gene in E. coli → Humulin — world's first recombinant drug, 1982)
- Hepatitis B vaccine (recombinant HBsAg)
- Erythropoietin, Growth hormone, Interferon
*Why A is wrong:* DNA amplification = PCR — not restriction enzymes.
*Why C is wrong:* RNA → DNA = Reverse Transcriptase — different enzyme.
*Why D is wrong:* Protein synthesis = ribosomes (translation) — not restriction enzymes.
- Discovered by Werner Arber, Daniel Nathans, Hamilton Smith (Nobel Prize 1978)
- Example: EcoRI cuts at GAATTC sequence → produces sticky ends (5'-AATT-3')
- Sticky ends: complementary overhangs that allow DNA from different organisms to hybridise (join)
Recombinant DNA technology process:
1. Restriction enzyme cuts both GENE OF INTEREST and VECTOR (plasmid) at same recognition site
2. DNA ligase joins the gene into the vector → RECOMBINANT DNA
3. Vector introduced into host cell (E. coli, yeast) → host replicates → gene expressed → protein produced
Applications:
- Insulin production (human insulin gene in E. coli → Humulin — world's first recombinant drug, 1982)
- Hepatitis B vaccine (recombinant HBsAg)
- Erythropoietin, Growth hormone, Interferon
*Why A is wrong:* DNA amplification = PCR — not restriction enzymes.
*Why C is wrong:* RNA → DNA = Reverse Transcriptase — different enzyme.
*Why D is wrong:* Protein synthesis = ribosomes (translation) — not restriction enzymes.
Q250HardBPSC Prelims
Stem cells are unique because they have the ability to:
AReplicate only in laboratory conditions without any special medium
BDifferentiate into any specialised cell type in the body (pluripotency) and self-renew
CProduce antibodies against any pathogen
DAbsorb nutrients directly from blood without organ mediation
Show Answer
✔ B — Differentiate into any specialised cell type in the body (pluripotency) and self-renew
Stem cells: undifferentiated cells with two defining properties:
1. Self-renewal: can divide indefinitely (maintenance of stem cell pool)
2. Differentiation potential: can become specialised cell types
Types based on potency:
- Totipotent (zygote, 2-4 cell stage): can form ENTIRE organism including placenta
- Pluripotent (embryonic stem cells/iPSCs): can form ANY cell type of the body (3 germ layers), but not placenta
- Multipotent (adult stem cells — haematopoietic, mesenchymal): can form cells of one lineage
- Unipotent: only one cell type
Induced Pluripotent Stem Cells (iPSCs): Shinya Yamanaka (Nobel 2012) — reprogrammed adult cells (skin) → pluripotent by adding 4 transcription factors (OSKM factors). Avoids ethical issues of embryonic stem cells.
Applications: regenerative medicine (spinal cord repair, heart repair), drug testing, disease modelling.
*Why A is wrong:* Stem cells require specialised culture media (growth factors, feeder cells or extracellular matrix) — they don't grow without special conditions.
*Why C is wrong:* Antibody production = B-lymphocytes (from haematopoietic stem cells, but stem cells themselves don't produce antibodies).
*Why D is wrong:* Nutrient absorption from blood is done by all metabolically active cells — not a stem cell-specific property.
1. Self-renewal: can divide indefinitely (maintenance of stem cell pool)
2. Differentiation potential: can become specialised cell types
Types based on potency:
- Totipotent (zygote, 2-4 cell stage): can form ENTIRE organism including placenta
- Pluripotent (embryonic stem cells/iPSCs): can form ANY cell type of the body (3 germ layers), but not placenta
- Multipotent (adult stem cells — haematopoietic, mesenchymal): can form cells of one lineage
- Unipotent: only one cell type
Induced Pluripotent Stem Cells (iPSCs): Shinya Yamanaka (Nobel 2012) — reprogrammed adult cells (skin) → pluripotent by adding 4 transcription factors (OSKM factors). Avoids ethical issues of embryonic stem cells.
Applications: regenerative medicine (spinal cord repair, heart repair), drug testing, disease modelling.
*Why A is wrong:* Stem cells require specialised culture media (growth factors, feeder cells or extracellular matrix) — they don't grow without special conditions.
*Why C is wrong:* Antibody production = B-lymphocytes (from haematopoietic stem cells, but stem cells themselves don't produce antibodies).
*Why D is wrong:* Nutrient absorption from blood is done by all metabolically active cells — not a stem cell-specific property.
Animal Kingdom
Q251EasyBPSC Prelims
The phylum Chordata includes all animals with which common characteristic?
AHard external skeleton (exoskeleton)
BRadial symmetry
CNotochord at some stage of development
DEight legs and two body segments
Show Answer
✔ C — Notochord at some stage of development
Phylum Chordata: defined by 4 fundamental characteristics (at some point in development):
1. Notochord: rod-like structure providing support
2. Dorsal hollow nerve cord (becomes brain and spinal cord)
3. Pharyngeal gill slits (or pharyngeal pouches)
4. Post-anal tail
Sub-phyla:
- Urochordata (Tunicates): sessile marine animals — larva has all chordate features, adult loses most
- Cephalochordata (Amphioxus/Branchiostoma): amphioxus has notochord throughout life
- Vertebrata: notochord replaced by vertebral column (backbone) — fish, amphibians, reptiles, birds, mammals
Classes of Vertebrata:
- Cyclostomata (jawless fish: lamprey, hagfish)
- Chondrichthyes (cartilaginous fish: shark, ray)
- Osteichthyes (bony fish: rohu, catla, carp)
- Amphibia (frog, toad, salamander)
- Reptilia (lizard, snake, crocodile, turtle)
- Aves (birds)
- Mammalia (mammals)
*Why A is wrong:* Hard exoskeleton = Phylum Arthropoda (insects, crustaceans) — not chordates.
*Why B is wrong:* Radial symmetry = Phylum Echinodermata (starfish), Cnidaria (jellyfish) — most chordates are bilaterally symmetrical.
*Why D is wrong:* 8 legs and 2 body segments (cephalothorax + abdomen) = Class Arachnida (spiders, scorpions) — Arthropoda.
1. Notochord: rod-like structure providing support
2. Dorsal hollow nerve cord (becomes brain and spinal cord)
3. Pharyngeal gill slits (or pharyngeal pouches)
4. Post-anal tail
Sub-phyla:
- Urochordata (Tunicates): sessile marine animals — larva has all chordate features, adult loses most
- Cephalochordata (Amphioxus/Branchiostoma): amphioxus has notochord throughout life
- Vertebrata: notochord replaced by vertebral column (backbone) — fish, amphibians, reptiles, birds, mammals
Classes of Vertebrata:
- Cyclostomata (jawless fish: lamprey, hagfish)
- Chondrichthyes (cartilaginous fish: shark, ray)
- Osteichthyes (bony fish: rohu, catla, carp)
- Amphibia (frog, toad, salamander)
- Reptilia (lizard, snake, crocodile, turtle)
- Aves (birds)
- Mammalia (mammals)
*Why A is wrong:* Hard exoskeleton = Phylum Arthropoda (insects, crustaceans) — not chordates.
*Why B is wrong:* Radial symmetry = Phylum Echinodermata (starfish), Cnidaria (jellyfish) — most chordates are bilaterally symmetrical.
*Why D is wrong:* 8 legs and 2 body segments (cephalothorax + abdomen) = Class Arachnida (spiders, scorpions) — Arthropoda.
Q252MediumBPSC Prelims
Identify the correct classification of the Indian Cobra (Naja naja):
AKingdom Animalia → Phylum Chordata → Class Amphibia → Order Squamata
BKingdom Animalia → Phylum Chordata → Class Reptilia → Order Squamata
CKingdom Animalia → Phylum Arthropoda → Class Insecta → Order Squamata
DKingdom Animalia → Phylum Chordata → Class Mammalia → Order Squamata
Show Answer
✔ B — Kingdom Animalia → Phylum Chordata → Class Reptilia → Order Squamata
Indian Cobra (Naja naja) classification:
- Kingdom: Animalia
- Phylum: Chordata
- Sub-phylum: Vertebrata
- Class: Reptilia
- Order: Squamata (scaled reptiles: snakes + lizards)
- Sub-order: Serpentes (snakes)
- Family: Elapidae
- Genus: Naja
- Species: naja
Characteristics of Reptiles:
- Dry, scaly skin (keratin scales — no slime)
- Ectothermic (cold-blooded)
- Breathe through lungs (no gills)
- Lay amniotic eggs (on land — leathery shell)
- 3-chambered heart (4-chambered in crocodiles)
- Excrete uric acid (water conservation)
India's "Big Four" venomous snakes: Indian Cobra (Naja naja), Common Krait (Bungarus caeruleus), Russell's Viper (Daboia russelii), Saw-scaled Viper (Echis carinatus).
*Why A is wrong:* Amphibia = frogs, toads, salamanders — different characteristics (moist skin, aquatic larvae).
*Why C is wrong:* Arthropoda = insects, spiders, crustaceans — completely different phylum.
*Why D is wrong:* Mammalia = warm-blooded, hair, mammary glands — snakes are cold-blooded and lay eggs.
- Kingdom: Animalia
- Phylum: Chordata
- Sub-phylum: Vertebrata
- Class: Reptilia
- Order: Squamata (scaled reptiles: snakes + lizards)
- Sub-order: Serpentes (snakes)
- Family: Elapidae
- Genus: Naja
- Species: naja
Characteristics of Reptiles:
- Dry, scaly skin (keratin scales — no slime)
- Ectothermic (cold-blooded)
- Breathe through lungs (no gills)
- Lay amniotic eggs (on land — leathery shell)
- 3-chambered heart (4-chambered in crocodiles)
- Excrete uric acid (water conservation)
India's "Big Four" venomous snakes: Indian Cobra (Naja naja), Common Krait (Bungarus caeruleus), Russell's Viper (Daboia russelii), Saw-scaled Viper (Echis carinatus).
*Why A is wrong:* Amphibia = frogs, toads, salamanders — different characteristics (moist skin, aquatic larvae).
*Why C is wrong:* Arthropoda = insects, spiders, crustaceans — completely different phylum.
*Why D is wrong:* Mammalia = warm-blooded, hair, mammary glands — snakes are cold-blooded and lay eggs.
Q253MediumBPSC Prelims
Which characteristic distinguishes mammals from all other vertebrates?
APresence of a four-chambered heart
BWarm-bloodedness (endothermy)
CHaving hair/fur and mammary glands that produce milk
DBreathing through lungs
Show Answer
✔ C — Having hair/fur and mammary glands that produce milk
Mammals (Class Mammalia): defined by TWO unique characteristics:
1. Hair or fur (at some life stage — even whales have hair as fetuses)
2. Mammary glands producing milk to nurse young — origin of the name "Mammalia"
Sub-classes of Mammalia:
- Protheria (Monotremes): lay eggs (platypus, echidna) — most primitive
- Metatheria (Marsupials): pouched mammals (kangaroo, koala) — give birth to very underdeveloped young
- Eutheria (Placental mammals): full pregnancy; young nourished via placenta — humans, whales, bats, elephants, dogs
*Why A is wrong:* Four-chambered heart is also found in birds (Aves) — not exclusive to mammals.
*Why B is wrong:* Warm-bloodedness (endothermy) is also found in birds — not exclusive to mammals.
*Why D is wrong:* Breathing through lungs is also found in adult amphibians, reptiles, and birds — not mammal-exclusive.
1. Hair or fur (at some life stage — even whales have hair as fetuses)
2. Mammary glands producing milk to nurse young — origin of the name "Mammalia"
Sub-classes of Mammalia:
- Protheria (Monotremes): lay eggs (platypus, echidna) — most primitive
- Metatheria (Marsupials): pouched mammals (kangaroo, koala) — give birth to very underdeveloped young
- Eutheria (Placental mammals): full pregnancy; young nourished via placenta — humans, whales, bats, elephants, dogs
*Why A is wrong:* Four-chambered heart is also found in birds (Aves) — not exclusive to mammals.
*Why B is wrong:* Warm-bloodedness (endothermy) is also found in birds — not exclusive to mammals.
*Why D is wrong:* Breathing through lungs is also found in adult amphibians, reptiles, and birds — not mammal-exclusive.
Q254HardBPSC Prelims
In which of the following does a sponge (Porifera) differ from all other animal phyla?
AHaving a digestive system
BLacking true tissues (are acellular/cellular but lack organised tissues)
CBeing aquatic
DBeing heterotrophic (consuming other organisms for nutrition)
Show Answer
✔ B — Lacking true tissues (are acellular/cellular but lack organised tissues)
Porifera (Sponges):
- Simplest multicellular animals
- Acellular grade of organisation: cells are loosely associated; no true tissues or organs
- No nervous system, no muscles, no definite symmetry (mostly asymmetric)
- Body wall with pores (ostia): water enters through pores → central cavity (spongocoel) → exits through osculum
- Filter feeders: choanocytes (collar cells) with flagella create water current and filter food particles
- Mostly marine; a few freshwater species
- Reproduce asexually (budding, fragmentation, gemmules) and sexually
All other animal phyla have tissues (at least 2 tissue layers):
- Cnidaria: 2 tissue layers (diploblastic — ectoderm + endoderm)
- All other animals: 3 tissue layers (triploblastic — ectoderm + mesoderm + endoderm)
*Why A is wrong:* Sponges have no digestive system — intracellular digestion in individual cells. But this is a contrast with OTHER animals' digestive systems, not what makes sponges unique among all.
*Why C is wrong:* Many animals are aquatic — aquatic habitat is not unique to sponges.
*Why D is wrong:* Heterotrophy is characteristic of ALL animals — not unique to sponges.
- Simplest multicellular animals
- Acellular grade of organisation: cells are loosely associated; no true tissues or organs
- No nervous system, no muscles, no definite symmetry (mostly asymmetric)
- Body wall with pores (ostia): water enters through pores → central cavity (spongocoel) → exits through osculum
- Filter feeders: choanocytes (collar cells) with flagella create water current and filter food particles
- Mostly marine; a few freshwater species
- Reproduce asexually (budding, fragmentation, gemmules) and sexually
All other animal phyla have tissues (at least 2 tissue layers):
- Cnidaria: 2 tissue layers (diploblastic — ectoderm + endoderm)
- All other animals: 3 tissue layers (triploblastic — ectoderm + mesoderm + endoderm)
*Why A is wrong:* Sponges have no digestive system — intracellular digestion in individual cells. But this is a contrast with OTHER animals' digestive systems, not what makes sponges unique among all.
*Why C is wrong:* Many animals are aquatic — aquatic habitat is not unique to sponges.
*Why D is wrong:* Heterotrophy is characteristic of ALL animals — not unique to sponges.
Bihar-Specific Biology
Q258EasyBPSC Prelims
Bihar's state animal is:
ABengal Tiger (Panthera tigris)
BGangetic River Dolphin (Platanista gangetica)
CIndian Elephant (Elephas maximus)
DIndian One-Horned Rhinoceros (Rhinoceros unicornis)
Show Answer
✔ B — Gangetic River Dolphin (Platanista gangetica)
Bihar's state animal: Gangetic River Dolphin (Platanista gangetica) — Susu
- Also declared India's National Aquatic Animal in 2009
- Blind (eyes vestigial — navigate by echolocation)
- Found in Ganga, Gandak, Kosi rivers in Bihar
- Bihar has the largest population in India: ~500-600 dolphins
Bihar state symbols:
- State animal: Gangetic River Dolphin (Platanista gangetica) — Susu
- State bird: House Sparrow (Passer domesticus)
- State tree: Peepal (Ficus religiosa)
- State flower: Marigold (Tagetes erecta)
- State fish: Mango fish / Topse (Polynemus paradiseus)
*Why A is wrong:* Bengal Tiger = National Animal of India; State Animal of West Bengal, Madhya Pradesh, etc.
*Why C is wrong:* Indian Elephant = State Animal of Kerala, Karnataka (forest elephant).
*Why D is wrong:* One-horned Rhinoceros = State Animal of Assam (Kaziranga famous for rhinos); Bihar has a rhino reintroduction programme at Valmiki NP.
- Also declared India's National Aquatic Animal in 2009
- Blind (eyes vestigial — navigate by echolocation)
- Found in Ganga, Gandak, Kosi rivers in Bihar
- Bihar has the largest population in India: ~500-600 dolphins
Bihar state symbols:
- State animal: Gangetic River Dolphin (Platanista gangetica) — Susu
- State bird: House Sparrow (Passer domesticus)
- State tree: Peepal (Ficus religiosa)
- State flower: Marigold (Tagetes erecta)
- State fish: Mango fish / Topse (Polynemus paradiseus)
*Why A is wrong:* Bengal Tiger = National Animal of India; State Animal of West Bengal, Madhya Pradesh, etc.
*Why C is wrong:* Indian Elephant = State Animal of Kerala, Karnataka (forest elephant).
*Why D is wrong:* One-horned Rhinoceros = State Animal of Assam (Kaziranga famous for rhinos); Bihar has a rhino reintroduction programme at Valmiki NP.
Q259MediumBPSC Prelims
Valmiki National Park in West Champaran district is significant because:
AIt is Bihar's only hill station and houses snow leopards
BIt is Bihar's only national park, part of the Terai ecosystem, home to Bengal tigers and gharials
CIt is famous for marine biodiversity and coral reefs in the Ganga delta
DIt is entirely reserved for migratory birds from Siberia and Central Asia
Show Answer
✔ B — It is Bihar's only national park, part of the Terai ecosystem, home to Bengal tigers and gharials
Valmiki National Park:
- Location: West Champaran district, Bihar — along the Nepal border (Gandak River)
- Status: Only National Park in Bihar; also a Tiger Reserve (Project Tiger)
- Area: 898.45 km² (core zone); Valmiki Wildlife Sanctuary: 693 km² surrounds it
- Ecosystem: Terai (sub-Himalayan floodplain) — sal forest, alluvial grasslands, marshes
Key wildlife:
- Bengal Tiger (Panthera tigris tigris) — ~50-60 tigers
- Indian One-horned Rhinoceros (Rhinoceros unicornis) — reintroduced from Assam
- Gangetic River Dolphin (Platanista gangetica) — in Gandak river
- Gharial (Gavialis gangeticus) — critically endangered; Gandak river
- Gaur (Indian bison), Leopard, Sloth Bear, Wild Boar
- Elephant (seasonal migrants from Nepal)
*Why A is wrong:* Bihar has no hill stations or snow leopards (Bihar is a plains state).
*Why C is wrong:* Bihar is a landlocked state with no marine ecosystem.
*Why D is wrong:* While migratory birds visit, the park's primary significance is its Tiger Reserve and diverse mammal fauna.
- Location: West Champaran district, Bihar — along the Nepal border (Gandak River)
- Status: Only National Park in Bihar; also a Tiger Reserve (Project Tiger)
- Area: 898.45 km² (core zone); Valmiki Wildlife Sanctuary: 693 km² surrounds it
- Ecosystem: Terai (sub-Himalayan floodplain) — sal forest, alluvial grasslands, marshes
Key wildlife:
- Bengal Tiger (Panthera tigris tigris) — ~50-60 tigers
- Indian One-horned Rhinoceros (Rhinoceros unicornis) — reintroduced from Assam
- Gangetic River Dolphin (Platanista gangetica) — in Gandak river
- Gharial (Gavialis gangeticus) — critically endangered; Gandak river
- Gaur (Indian bison), Leopard, Sloth Bear, Wild Boar
- Elephant (seasonal migrants from Nepal)
*Why A is wrong:* Bihar has no hill stations or snow leopards (Bihar is a plains state).
*Why C is wrong:* Bihar is a landlocked state with no marine ecosystem.
*Why D is wrong:* While migratory birds visit, the park's primary significance is its Tiger Reserve and diverse mammal fauna.
Q260HardBPSC Prelims
The Kanwar Lake (Kabar Tal) in Begusarai district is significant because:
AIt is the world's largest lake, famous for fishing
BIt is Asia's largest freshwater oxbow lake and one of India's most important waterbird habitats
CIt is a man-made reservoir supplying drinking water to Patna
DIt is famous for its hot springs and geothermal energy potential
Show Answer
✔ B — It is Asia's largest freshwater oxbow lake and one of India's most important waterbird habitats
Kanwar Lake (Kabar Tal):
- Location: Begusarai district, Bihar
- Type: Oxbow lake (formed when a river meander is cut off — from ancient Buri Gandak river)
- Significance: Asia's largest freshwater oxbow lake; Ramsar site (designated 1990)
- Area: ~67 km² (historical) — reduced to ~30-40 km² due to encroachment and siltation
- Status: Kanwar Lake Bird Sanctuary; under IUCN conservation
Biodiversity:
- Migratory birds: ~60,000+ birds in peak season from Siberia, Central Asia, Europe (October-March)
- Species: Sarus Crane (Grus antigone) — tallest flying bird; Spot-billed Pelican, Bar-headed Geese, Brahminy Duck, Pintail, Garganey
- Resident birds: Purple Moorhen, Pheasant-tailed Jacana, Indian Spot-billed Duck
- Fish: 40+ species supporting local fishing communities
Threats: encroachment (farming, fish farming), siltation, pollution from chemical factories (Barauni fertilizer plant).
*Why A is wrong:* Kanwar is not the world's largest lake (Caspian Sea is) — it's Asia's largest freshwater OXBOW lake.
*Why C is wrong:* Kanwar is not a man-made reservoir; it's a natural oxbow lake.
*Why D is wrong:* Bihar has no hot springs or significant geothermal activity.
- Location: Begusarai district, Bihar
- Type: Oxbow lake (formed when a river meander is cut off — from ancient Buri Gandak river)
- Significance: Asia's largest freshwater oxbow lake; Ramsar site (designated 1990)
- Area: ~67 km² (historical) — reduced to ~30-40 km² due to encroachment and siltation
- Status: Kanwar Lake Bird Sanctuary; under IUCN conservation
Biodiversity:
- Migratory birds: ~60,000+ birds in peak season from Siberia, Central Asia, Europe (October-March)
- Species: Sarus Crane (Grus antigone) — tallest flying bird; Spot-billed Pelican, Bar-headed Geese, Brahminy Duck, Pintail, Garganey
- Resident birds: Purple Moorhen, Pheasant-tailed Jacana, Indian Spot-billed Duck
- Fish: 40+ species supporting local fishing communities
Threats: encroachment (farming, fish farming), siltation, pollution from chemical factories (Barauni fertilizer plant).
*Why A is wrong:* Kanwar is not the world's largest lake (Caspian Sea is) — it's Asia's largest freshwater OXBOW lake.
*Why C is wrong:* Kanwar is not a man-made reservoir; it's a natural oxbow lake.
*Why D is wrong:* Bihar has no hot springs or significant geothermal activity.
Q264HardBPSC Prelims
The "Acute Encephalitis Syndrome" (AES) outbreaks in Muzaffarpur were caused by:
AEncephalitis lethargica virus (mosquito-borne)
BHypoglycin A toxin from raw litchi consumed by malnourished children + hypoglycaemia
CHeavy metal poisoning from Muzaffarpur's industrial effluents
DJapanese Encephalitis virus (mosquito-borne) exclusively
Show Answer
✔ B — Hypoglycin A toxin from raw litchi consumed by malnourished children + hypoglycaemia
Muzaffarpur AES Outbreak (biggest: 2019, 151 deaths):
Investigation (ICMR, CDC, Government): linked to:
1. Hypoglycin A (toxic compound in raw/unripe litchi) + MCPG (methylenecyclopropylglycine) — inhibit fatty acid beta-oxidation and gluconeogenesis
2. Malnourished children with no evening meal: overnight fasting → no glycogen stores
3. Children eating raw litchi from orchards → hypoglycin A accumulation → severe hypoglycaemia (low blood sugar) → brain energy crisis → encephalopathy, seizures, coma, death
4. Typically affects children aged 1-10 years; early morning sudden onset
Clinical: low blood sugar (<50 mg/dL) WITHOUT fever (differentiates from Japanese Encephalitis which has fever).
Treatment: emergency glucose infusion (successful if given early); NIMHANS and ICU support.
Prevention: children should not eat raw litchi; must have evening meal; no litchi on empty stomach.
*Why A is wrong:* "Encephalitis lethargica" is a historical 1920s pandemic — not the cause here.
*Why C is wrong:* Heavy metals cause chronic poisoning — not sudden seasonal outbreaks.
*Why D is wrong:* Japanese Encephalitis (JE) ALSO occurs in Bihar but presents differently (fever, mosquito season, Culex vector). The Muzaffarpur AES was NOT exclusively JE.
Investigation (ICMR, CDC, Government): linked to:
1. Hypoglycin A (toxic compound in raw/unripe litchi) + MCPG (methylenecyclopropylglycine) — inhibit fatty acid beta-oxidation and gluconeogenesis
2. Malnourished children with no evening meal: overnight fasting → no glycogen stores
3. Children eating raw litchi from orchards → hypoglycin A accumulation → severe hypoglycaemia (low blood sugar) → brain energy crisis → encephalopathy, seizures, coma, death
4. Typically affects children aged 1-10 years; early morning sudden onset
Clinical: low blood sugar (<50 mg/dL) WITHOUT fever (differentiates from Japanese Encephalitis which has fever).
Treatment: emergency glucose infusion (successful if given early); NIMHANS and ICU support.
Prevention: children should not eat raw litchi; must have evening meal; no litchi on empty stomach.
*Why A is wrong:* "Encephalitis lethargica" is a historical 1920s pandemic — not the cause here.
*Why C is wrong:* Heavy metals cause chronic poisoning — not sudden seasonal outbreaks.
*Why D is wrong:* Japanese Encephalitis (JE) ALSO occurs in Bihar but presents differently (fever, mosquito season, Culex vector). The Muzaffarpur AES was NOT exclusively JE.
Bihar-Specific Biology — Agriculture
Q261MediumBPSC Prelims
Bihar is known as a major producer of which horticultural crop?
ATea and coffee
BLitchi (Lychee) and mango, especially Muzaffarpur litchi and Hajipur banana
CRubber and coconut
DApple and walnut
Show Answer
✔ B — Litchi (Lychee) and mango, especially Muzaffarpur litchi and Hajipur banana
Bihar's horticultural significance:
Litchi (Litchi chinensis):
- Muzaffarpur district: largest litchi producer in India (and among top globally); Bihar accounts for ~75% of India's total litchi production
- Season: May-June; famous variety: "Shahi" litchi (GI tagged)
- Economic importance: litchi export hub; Muzaffarpur's economy heavily depends on litchi
Mango:
- Bihar's Hajipur and entire Ganga-Gandak belt: famous for Malda, Bombai, Zardalu (Bhagalpur Zardalu GI tagged) mangoes
- Bhagalpur Zardalu mango: Geographical Indication (GI) tag — recognized for its unique yellow colour and sweetness
Banana:
- Hajipur (Vaishali district): famous for "Chinia" banana variety
- Bihar ranks among top 3 states in banana production
Other Bihar horticulture: Darbhanga makhaniya lemon, Jahanabad amla, Nalanda's onion and potato.
*Why A is wrong:* Tea (Assam, West Bengal, Darjeeling) and Coffee (Karnataka, Kerala, Tamil Nadu) — not Bihar crops.
*Why C is wrong:* Rubber (Kerala, Tamil Nadu) and Coconut (Kerala coast) — tropical coastal crops.
*Why D is wrong:* Apple (Himachal Pradesh, Jammu & Kashmir) and Walnut (J&K) — temperate hill crops.
Litchi (Litchi chinensis):
- Muzaffarpur district: largest litchi producer in India (and among top globally); Bihar accounts for ~75% of India's total litchi production
- Season: May-June; famous variety: "Shahi" litchi (GI tagged)
- Economic importance: litchi export hub; Muzaffarpur's economy heavily depends on litchi
Mango:
- Bihar's Hajipur and entire Ganga-Gandak belt: famous for Malda, Bombai, Zardalu (Bhagalpur Zardalu GI tagged) mangoes
- Bhagalpur Zardalu mango: Geographical Indication (GI) tag — recognized for its unique yellow colour and sweetness
Banana:
- Hajipur (Vaishali district): famous for "Chinia" banana variety
- Bihar ranks among top 3 states in banana production
Other Bihar horticulture: Darbhanga makhaniya lemon, Jahanabad amla, Nalanda's onion and potato.
*Why A is wrong:* Tea (Assam, West Bengal, Darjeeling) and Coffee (Karnataka, Kerala, Tamil Nadu) — not Bihar crops.
*Why C is wrong:* Rubber (Kerala, Tamil Nadu) and Coconut (Kerala coast) — tropical coastal crops.
*Why D is wrong:* Apple (Himachal Pradesh, Jammu & Kashmir) and Walnut (J&K) — temperate hill crops.
Q262HardBPSC Prelims
Makhana (Fox Nuts/Lotus Seeds) cultivation is associated with which districts of Bihar?
ABhojpur and Rohtas districts (western Bihar)
BDarbhanga, Madhubani, Sitamarhi districts (Mithila region, northern Bihar)
CGaya and Nalanda districts (Magadh region)
DKatihar and Purnia districts (eastern Bihar)
Show Answer
✔ B — Darbhanga, Madhubani, Sitamarhi districts (Mithila region, northern Bihar)
Makhana (Euryale ferox) — Fox nuts/Water lotus seeds:
- Bihar produces 90% of India's Makhana and India accounts for 90% of global production
- Primary cultivation areas: Mithila region — Darbhanga, Madhubani, Saharsa, Sitamarhi, Supaul, Khagaria districts (waterlogged areas of North Bihar)
- Cultivation: Floating aquatic plant grown in ponds, swamps, and low-lying flooded fields
- GI Tag: Mithila Makhana received Geographical Indication (GI) tag (2022)
- Nutritional value: high protein (9.7%), calcium, iron; used in festive foods, kheer, phool makhana snacks
- Dhani: popped makhana (heated in sand) — cottage industry providing livelihoods
Economic importance: ₹3,000-4,000 crore industry; export to USA, UK, Middle East.
One District One Product (ODOP): Makhana identified for Darbhanga, Madhubani.
*Why A is wrong:* Western Bihar (Bhojpur, Rohtas) grows wheat, paddy, arhar — not makhana (different soil and water conditions).
*Why C is wrong:* Gaya-Nalanda = rice, vegetable, arhar zone — Mahabodhi region, not makhana.
*Why D is wrong:* Katihar-Purnia = jute, maize zone — eastern Bihar doesn't have the same waterlogged conditions.
- Bihar produces 90% of India's Makhana and India accounts for 90% of global production
- Primary cultivation areas: Mithila region — Darbhanga, Madhubani, Saharsa, Sitamarhi, Supaul, Khagaria districts (waterlogged areas of North Bihar)
- Cultivation: Floating aquatic plant grown in ponds, swamps, and low-lying flooded fields
- GI Tag: Mithila Makhana received Geographical Indication (GI) tag (2022)
- Nutritional value: high protein (9.7%), calcium, iron; used in festive foods, kheer, phool makhana snacks
- Dhani: popped makhana (heated in sand) — cottage industry providing livelihoods
Economic importance: ₹3,000-4,000 crore industry; export to USA, UK, Middle East.
One District One Product (ODOP): Makhana identified for Darbhanga, Madhubani.
*Why A is wrong:* Western Bihar (Bhojpur, Rohtas) grows wheat, paddy, arhar — not makhana (different soil and water conditions).
*Why C is wrong:* Gaya-Nalanda = rice, vegetable, arhar zone — Mahabodhi region, not makhana.
*Why D is wrong:* Katihar-Purnia = jute, maize zone — eastern Bihar doesn't have the same waterlogged conditions.
Ecology — Bihar Specific
Q263MediumBPSC Prelims
The Ganga river is ecologically important for Bihar because:
AIt provides hydroelectric power supply to all of Bihar's rural areas
BIt supports fisheries, agriculture (alluvial soil), biodiversity (dolphins, gharials, turtles), and drinking water for millions
CIt is the source of all underground water in Bihar
DIt primarily serves as a boundary between Bihar and Uttar Pradesh
Show Answer
✔ B — It supports fisheries, agriculture (alluvial soil), biodiversity (dolphins, gharials, turtles), and drinking water for millions
Ganga river's ecological importance for Bihar:
1. Agriculture: Gangetic alluvial plain — Indo-Gangetic plain deposits some of the most fertile soil in the world (silt, clay, sand from Himalayas). Rice, wheat, pulses production.
2. Fisheries: Bihar's inland fisheries — Ganga, Kosi, Gandak, Sone rivers. Species: Rohu (Labeo rohita), Catla (Catla catla), Mrigal (Cirrhinus mrigala), Hilsa (Tenualosa ilisha). Bihar's inland fish production: ~5.5 lakh metric tonnes.
3. Biodiversity:
- Gangetic River Dolphin (Platanista gangetica): Bihar state animal
- Gharial (Gavialis gangeticus): critically endangered; in Gandak, Ghaghara, Son rivers
- Indian Softshell Turtle (Nilssonia gangetica): critically endangered
- Indian Skimmer (Rynchops albicollis): rare bird on Ganga sandbars
4. Drinking water: Patna, Bhagalpur, Munger, Gaya (Son river) depend on river water supply.
5. Cultural: Holy river; Bihar's Chhath Puja (Ganga Snan); Rajgir hot springs.
*Why A is wrong:* Ganga provides NO hydroelectric power in Bihar (Bihar's terrain is flat; dams on Ganga are upstream in Uttarakhand).
*Why C is wrong:* Underground water is recharged through rain and river seepage — not solely from Ganga.
*Why D is wrong:* Bihar-UP boundary is along the Karmanasha river (not Ganga throughout); Ganga flows WITHIN Bihar.
1. Agriculture: Gangetic alluvial plain — Indo-Gangetic plain deposits some of the most fertile soil in the world (silt, clay, sand from Himalayas). Rice, wheat, pulses production.
2. Fisheries: Bihar's inland fisheries — Ganga, Kosi, Gandak, Sone rivers. Species: Rohu (Labeo rohita), Catla (Catla catla), Mrigal (Cirrhinus mrigala), Hilsa (Tenualosa ilisha). Bihar's inland fish production: ~5.5 lakh metric tonnes.
3. Biodiversity:
- Gangetic River Dolphin (Platanista gangetica): Bihar state animal
- Gharial (Gavialis gangeticus): critically endangered; in Gandak, Ghaghara, Son rivers
- Indian Softshell Turtle (Nilssonia gangetica): critically endangered
- Indian Skimmer (Rynchops albicollis): rare bird on Ganga sandbars
4. Drinking water: Patna, Bhagalpur, Munger, Gaya (Son river) depend on river water supply.
5. Cultural: Holy river; Bihar's Chhath Puja (Ganga Snan); Rajgir hot springs.
*Why A is wrong:* Ganga provides NO hydroelectric power in Bihar (Bihar's terrain is flat; dams on Ganga are upstream in Uttarakhand).
*Why C is wrong:* Underground water is recharged through rain and river seepage — not solely from Ganga.
*Why D is wrong:* Bihar-UP boundary is along the Karmanasha river (not Ganga throughout); Ganga flows WITHIN Bihar.
Environmental Biology
Q265MediumBPSC Prelims
Which of the following is India's first Biosphere Reserve?
ASundarbans Biosphere Reserve (West Bengal)
BNilgiri Biosphere Reserve (Tamil Nadu, Kerala, Karnataka)
CGreat Rann of Kutch Biosphere Reserve (Gujarat)
DPachmarhi Biosphere Reserve (Madhya Pradesh)
Show Answer
✔ B — Nilgiri Biosphere Reserve (Tamil Nadu, Kerala, Karnataka)
Nilgiri Biosphere Reserve: designated in 1986 as India's FIRST Biosphere Reserve (UNESCO Man and Biosphere Programme).
- Area: 5,520 km² (largest in India by core zone)
- States: Tamil Nadu, Kerala, Karnataka
- Major ecosystems: tropical evergreen forests, shola grasslands
- Notable wildlife: Nilgiri Tahr (endangered), Asian Elephant, Bengal Tiger, Leopard, Lion-tailed Macaque
Biosphere Reserves (UNESCO MAB Programme): areas designated to promote sustainable use of biological resources while conserving biodiversity.
Three zones:
- Core zone: strictly protected, no human activity
- Buffer zone: limited research and education allowed
- Transition zone: human settlements and sustainable use
India has 18 Biosphere Reserves; 12 are included in UNESCO's World Network of Biosphere Reserves.
*Why A is wrong:* Sundarbans BR designated in 1989 — third in India.
*Why C is wrong:* Rann of Kutch BR designated in 2008.
*Why D is wrong:* Pachmarhi BR designated in 1999.
- Area: 5,520 km² (largest in India by core zone)
- States: Tamil Nadu, Kerala, Karnataka
- Major ecosystems: tropical evergreen forests, shola grasslands
- Notable wildlife: Nilgiri Tahr (endangered), Asian Elephant, Bengal Tiger, Leopard, Lion-tailed Macaque
Biosphere Reserves (UNESCO MAB Programme): areas designated to promote sustainable use of biological resources while conserving biodiversity.
Three zones:
- Core zone: strictly protected, no human activity
- Buffer zone: limited research and education allowed
- Transition zone: human settlements and sustainable use
India has 18 Biosphere Reserves; 12 are included in UNESCO's World Network of Biosphere Reserves.
*Why A is wrong:* Sundarbans BR designated in 1989 — third in India.
*Why C is wrong:* Rann of Kutch BR designated in 2008.
*Why D is wrong:* Pachmarhi BR designated in 1999.
Q266EasyBPSC Prelims
The IUCN Red List classifies species into different categories. "Critically Endangered" means:
AThe species has already become extinct in the wild
BThe species faces an extremely high risk of extinction in the wild in the immediate future
CThe species is rare but not facing immediate extinction
DThe species is common but declining in numbers slowly
Show Answer
✔ B — The species faces an extremely high risk of extinction in the wild in the immediate future
IUCN Red List (International Union for Conservation of Nature): the world's most comprehensive assessment of species' conservation status.
IUCN Red List Categories (in order of threat):
1. Extinct (EX): no reasonable doubt that last individual has died (e.g., Dodo, Passenger Pigeon)
2. Extinct in the Wild (EW): survives only in captivity (e.g., Scimitar Oryx in wild)
3. Critically Endangered (CR): EXTREMELY HIGH risk of extinction (e.g., Gharial, White-rumped Vulture)
4. Endangered (EN): VERY HIGH risk (e.g., Snow Leopard, Asiatic Lion)
5. Vulnerable (VU): HIGH risk (e.g., Gangetic Dolphin, Bengal Tiger — globally)
6. Near Threatened (NT): close to qualifying as threatened
7. Least Concern (LC): abundant species (e.g., House Sparrow, Indian Crow)
8. Data Deficient (DD): insufficient data to assess
*Why A is wrong:* Already extinct in the wild = "Extinct in the Wild (EW)" category.
*Why C is wrong:* Rare but not immediate = "Near Threatened (NT)" or "Vulnerable (VU)".
*Why D is wrong:* Declining slowly = various categories depending on rate; common + declining slowly = "Near Threatened."
IUCN Red List Categories (in order of threat):
1. Extinct (EX): no reasonable doubt that last individual has died (e.g., Dodo, Passenger Pigeon)
2. Extinct in the Wild (EW): survives only in captivity (e.g., Scimitar Oryx in wild)
3. Critically Endangered (CR): EXTREMELY HIGH risk of extinction (e.g., Gharial, White-rumped Vulture)
4. Endangered (EN): VERY HIGH risk (e.g., Snow Leopard, Asiatic Lion)
5. Vulnerable (VU): HIGH risk (e.g., Gangetic Dolphin, Bengal Tiger — globally)
6. Near Threatened (NT): close to qualifying as threatened
7. Least Concern (LC): abundant species (e.g., House Sparrow, Indian Crow)
8. Data Deficient (DD): insufficient data to assess
*Why A is wrong:* Already extinct in the wild = "Extinct in the Wild (EW)" category.
*Why C is wrong:* Rare but not immediate = "Near Threatened (NT)" or "Vulnerable (VU)".
*Why D is wrong:* Declining slowly = various categories depending on rate; common + declining slowly = "Near Threatened."
Q267MediumBPSC Prelims
The "Green Revolution" in India involved which of the following?
ALarge-scale afforestation of wastelands using native tree species
BIntroduction of High-Yielding Variety (HYV) seeds, chemical fertilizers, irrigation, and pesticides to increase food grain production
CPromotion of organic farming and rejection of chemical inputs
DPlanting medicinal plants across government land for healthcare access
Show Answer
✔ B — Introduction of High-Yielding Variety (HYV) seeds, chemical fertilizers, irrigation, and pesticides to increase food grain production
Green Revolution in India:
- Period: 1960s-1970s
- Led by: M.S. Swaminathan (India) and Norman Borlaug (USA — Nobel Peace Prize 1970)
- Context: India facing severe food shortage; PL-480 food aid from USA; risk of famine
Key components:
1. High-Yielding Varieties (HYV): wheat (Sonora-64, Kalyan Sona), rice (IR-8 "miracle rice") — shorter stems, more grain per stalk
2. Chemical fertilizers: NPK (nitrogen, phosphorus, potassium) — massive use
3. Irrigation: tube wells, canal irrigation — reduced dependence on monsoon
4. Pesticides: control of pests
5. Credit and market support: minimum support price (MSP) for wheat/rice
Results: India went from food deficit to food self-sufficiency; wheat production tripled (1965-1980).
Regions: Punjab, Haryana, western UP — "Green Revolution belt"; Bihar benefited less.
Negative effects: soil degradation, water table depletion, loss of crop diversity, chemical pollution.
*Why A is wrong:* Afforestation = forestation programme — not Green Revolution.
*Why C is wrong:* Green Revolution was about MAXIMISING yield using chemicals — opposite of organic farming.
*Why D is wrong:* Medicinal plant cultivation is a separate programme — not Green Revolution.
- Period: 1960s-1970s
- Led by: M.S. Swaminathan (India) and Norman Borlaug (USA — Nobel Peace Prize 1970)
- Context: India facing severe food shortage; PL-480 food aid from USA; risk of famine
Key components:
1. High-Yielding Varieties (HYV): wheat (Sonora-64, Kalyan Sona), rice (IR-8 "miracle rice") — shorter stems, more grain per stalk
2. Chemical fertilizers: NPK (nitrogen, phosphorus, potassium) — massive use
3. Irrigation: tube wells, canal irrigation — reduced dependence on monsoon
4. Pesticides: control of pests
5. Credit and market support: minimum support price (MSP) for wheat/rice
Results: India went from food deficit to food self-sufficiency; wheat production tripled (1965-1980).
Regions: Punjab, Haryana, western UP — "Green Revolution belt"; Bihar benefited less.
Negative effects: soil degradation, water table depletion, loss of crop diversity, chemical pollution.
*Why A is wrong:* Afforestation = forestation programme — not Green Revolution.
*Why C is wrong:* Green Revolution was about MAXIMISING yield using chemicals — opposite of organic farming.
*Why D is wrong:* Medicinal plant cultivation is a separate programme — not Green Revolution.
Plant Biology
Q268MediumBPSC Prelims
Jute (Corchorus species) is an important commercial crop in Bihar. The economic part of the jute plant is:
ASeeds (used for making ropes)
BStem fibres (phloem fibres used for making gunny bags, sacks, rope)
CLeaves (used for food packaging)
DRoots (used for textile production)
Show Answer
✔ B — Stem fibres (phloem fibres used for making gunny bags, sacks, rope)
Jute (Corchorus capsularis and Corchorus olitorius): "Golden Fibre" — one of the cheapest natural fibres.
Economic part: Stem fibres (bast fibres / phloem fibres)
- Extracted by: Retting (soaking stems in water 10-20 days → bacteria loosen fibres from bark)
- After retting: fibres stripped, washed, dried → golden-coloured raw jute
- Uses: gunny bags (rice, wheat, sugar packaging), hessian cloth, rope, carpet backing, geotextiles
Jute cultivation in Bihar:
- Districts: Kishanganj, Purnia, Katihar, Supaul, Saharsa — eastern Bihar (high rainfall, alluvial soil)
- Bihar is India's 2nd largest jute producer (after West Bengal)
- Samastipur: jute research
India's jute industry: concentrated in West Bengal (Hooghly river basin); Dundee (Scotland) historical hub.
*Why A is wrong:* Jute seeds are small, inconspicuous — not commercially important.
*Why C is wrong:* Jute leaves can be eaten as a vegetable but are not the commercial fibre product.
*Why D is wrong:* Jute roots provide no commercial value.
Economic part: Stem fibres (bast fibres / phloem fibres)
- Extracted by: Retting (soaking stems in water 10-20 days → bacteria loosen fibres from bark)
- After retting: fibres stripped, washed, dried → golden-coloured raw jute
- Uses: gunny bags (rice, wheat, sugar packaging), hessian cloth, rope, carpet backing, geotextiles
Jute cultivation in Bihar:
- Districts: Kishanganj, Purnia, Katihar, Supaul, Saharsa — eastern Bihar (high rainfall, alluvial soil)
- Bihar is India's 2nd largest jute producer (after West Bengal)
- Samastipur: jute research
India's jute industry: concentrated in West Bengal (Hooghly river basin); Dundee (Scotland) historical hub.
*Why A is wrong:* Jute seeds are small, inconspicuous — not commercially important.
*Why C is wrong:* Jute leaves can be eaten as a vegetable but are not the commercial fibre product.
*Why D is wrong:* Jute roots provide no commercial value.
Bihar-Specific Agriculture
Q269HardBPSC Prelims
The Kosi river is called "Bihar's Sorrow" because:
AKosi water is too salty for irrigation use
BThe Kosi frequently changes its course and causes catastrophic flooding, destroying agriculture and settlements
CKosi has no water during the dry season, causing drought
DKosi's pollution kills fish and destroys river-based livelihoods
Show Answer
✔ B — The Kosi frequently changes its course and causes catastrophic flooding, destroying agriculture and settlements
Kosi River ("Bihar's Sorrow" / "Sorrow of Bihar"):
- Origin: Eastern Himalayas (Nepal); joins Ganga near Kursela (Katihar district)
- Major characteristic: Highly braided, frequently shifting course — moved ~110 km westward over 200 years
- Carries ENORMOUS sediment load from Himalayas → deposits in plains → river bed rises above surrounding land level → floods when levees breach
Kosi 2008 Flood (worst in 50 years):
- Embankment breach near Kusaha, Nepal (August 2008)
- Flooded: Supaul, Saharsa, Madhepura, Araria, Purnia districts
- Affected: ~3 million people; ~30,000 villages inundated; 527 deaths
- Estimated damage: ₹13,000 crore
Kosi floods: regular monsoon floods (annual); the 2008 flood was catastrophic because of embankment failure.
Kosi Project: multipurpose project (irrigation, flood control); Birpur Barrage (Supaul) and Hanuman Nagar Barrage (Nepal side).
*Why A is wrong:* Kosi water is not salty — it's fresh water used for irrigation.
*Why C is wrong:* Kosi has seasonal flow variation but does have water; it's flood, not drought, that's the problem.
*Why D is wrong:* Pollution is a concern but is not why it's called "Bihar's Sorrow."
- Origin: Eastern Himalayas (Nepal); joins Ganga near Kursela (Katihar district)
- Major characteristic: Highly braided, frequently shifting course — moved ~110 km westward over 200 years
- Carries ENORMOUS sediment load from Himalayas → deposits in plains → river bed rises above surrounding land level → floods when levees breach
Kosi 2008 Flood (worst in 50 years):
- Embankment breach near Kusaha, Nepal (August 2008)
- Flooded: Supaul, Saharsa, Madhepura, Araria, Purnia districts
- Affected: ~3 million people; ~30,000 villages inundated; 527 deaths
- Estimated damage: ₹13,000 crore
Kosi floods: regular monsoon floods (annual); the 2008 flood was catastrophic because of embankment failure.
Kosi Project: multipurpose project (irrigation, flood control); Birpur Barrage (Supaul) and Hanuman Nagar Barrage (Nepal side).
*Why A is wrong:* Kosi water is not salty — it's fresh water used for irrigation.
*Why C is wrong:* Kosi has seasonal flow variation but does have water; it's flood, not drought, that's the problem.
*Why D is wrong:* Pollution is a concern but is not why it's called "Bihar's Sorrow."
Environmental Biology — Biodiversity
Q270MediumBPSC Prelims
The term "endemic species" refers to:
ASpecies found everywhere in the world (cosmopolitan distribution)
BSpecies found only in a specific geographic region and nowhere else naturally
CSpecies that are invasive and have been introduced from other countries
DSpecies that are extinct but preserved in museums
Show Answer
✔ B — Species found only in a specific geographic region and nowhere else naturally
Endemic species: species whose natural range is confined to a specific geographic area — it occurs NOWHERE ELSE naturally.
- Scale varies: endemic to a country, state, mountain range, island, or river system
Examples:
- Nilgiri Tahr: endemic to Nilgiri Hills, Western Ghats (India)
- Lion-tailed Macaque: endemic to Western Ghats (India)
- Andaman Serpent Eagle: endemic to Andaman Islands
- Namdapha flying squirrel: endemic to Namdapha NP (Arunachal Pradesh)
Bihar's endemic/near-endemic species:
- Gangetic River Dolphin: range limited to Ganga-Brahmaputra-Indus river systems (South Asian endemism)
- Gharial: near-endemic to Indian subcontinent river systems
Biodiversity hotspots (Norman Myers): areas with high endemism AND high threat level.
India has 4 biodiversity hotspots: Western Ghats, Eastern Himalayas, Indo-Burma, Sundaland (part of Nicobar Islands).
*Why A is wrong:* Cosmopolitan = opposite of endemic (found worldwide, e.g., housefly, cockroach).
*Why C is wrong:* Invasive/introduced species = exotic species (the opposite of endemic).
*Why D is wrong:* Extinct species preserved in museums = type specimens — not "endemic" (endemic refers to living species' distribution).
- Scale varies: endemic to a country, state, mountain range, island, or river system
Examples:
- Nilgiri Tahr: endemic to Nilgiri Hills, Western Ghats (India)
- Lion-tailed Macaque: endemic to Western Ghats (India)
- Andaman Serpent Eagle: endemic to Andaman Islands
- Namdapha flying squirrel: endemic to Namdapha NP (Arunachal Pradesh)
Bihar's endemic/near-endemic species:
- Gangetic River Dolphin: range limited to Ganga-Brahmaputra-Indus river systems (South Asian endemism)
- Gharial: near-endemic to Indian subcontinent river systems
Biodiversity hotspots (Norman Myers): areas with high endemism AND high threat level.
India has 4 biodiversity hotspots: Western Ghats, Eastern Himalayas, Indo-Burma, Sundaland (part of Nicobar Islands).
*Why A is wrong:* Cosmopolitan = opposite of endemic (found worldwide, e.g., housefly, cockroach).
*Why C is wrong:* Invasive/introduced species = exotic species (the opposite of endemic).
*Why D is wrong:* Extinct species preserved in museums = type specimens — not "endemic" (endemic refers to living species' distribution).