Bihar Board 2026 Class 12th Biology Unofficial Answer Key: The Bihar School Examination Board (BSEB) has officially commenced the 2026 Intermediate Annual Examinations today, February 2, 2026. Approximately 13.18 lakh students began their Class 12 (Intermediate) exams at 1,762 centres across the state. As per the official schedule, the Bihar Board Class 12 Biology Examination 2026 was held today, from 9:30 AM to 12:45 PM. BSEB Class 12 Biology exam 2026 follows a 100-mark assessment structure, split between a 70-mark theory paper and a 30-mark practical exam. Students who appeared for the Bihar Board Class 12 Biology Theory Examination 2026 can check the Bihar Board 2026 Class 12th Biology Unofficial Answer Key available here.
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Bihar Board 2026 Class 12th Biology Unofficial Answer Key
Students can check the BSEB 2026 Class 12th Biology Unofficial Answer Key available in the table below.
| Bihar Board 2026 Class 12th Biology Questions | Bihar Board 2026 Class 12th Biology Answers |
| Question 1: If a person's blood group is AB, what would be his/her genotype? | I^A I^B |
| Question 2: How many types of gametes would be formed if the genotype of plant is AaBbCc ? | Eight |
| Question 3: Which of the following is not a chromosomal disorder ? | Haemophilia |
| Question 4: In which of the following animals does sex determination depend on the number of chromosome sets? | Honeybees |
| Question 5: Which of the following laws are based on monohybrid cross? | both A and B |
| Question 6: Fossils are found in which type of rocks? | sedimentary rocks |
| Question 7: Which of the following are examples of homologous organs in animals? | Homologous organs |
| Question 8: Which of the following was more like an ape? | Dryopithecus |
| Question 9: Which of the following enzymes allows lactose to enter the bacterial cell? | Permease |
| Question 10: Who stated that in double stranded DNA sum of purine nitrogenous bases is equal to the sum of pyrimidine nitrogenous bases? | Erwin Chargaff |
| Question 11: A typical nucleosome....... | Both A and B |
| Question 12: What did Hershey and Chase conclude on the basis of their experiments? | DNA from the virus enters the bacteria |
| Question 13: What is the process of removal of introns and mutual joining of icatic nexons called? | splicing |
| Question 14: Which of the following statements is incorrect about the code ? | All 64 codons code for amino acids |
| Question 15: How many mega-biodiversity countries are there in the world ? | 17 |
| Question 16: Which region got comparatively shorter span of time for species evolution and diversification due to frequent glaciation ? | Temperate regions |
| Question 17: Which is called the lungs of the earth ? | The Amazon Rainforest |
| Question 18: Which of the following species became extinct due to over- exploitation ? | Passenger pigeon |
| Question 19: Which of the following is not the primary consumer ecosystem ? | Grasshoppers |
| Question 20: How much percentage of photo-synthetically active radiation captured by plants ? | 2-10% |
| Question 22: What is the raw material for decomposition called ? | detritus |
| Question 23: What is secondary consumer called ? | primary carnivores |
| Question 24: What are those called which obtain energy and breaking dead organic matter or detritus ? | detritivores |
| Question 25: Which of the following is the pollinating agent of Ophrys ? | a species of bee |
| Question 26: Which of the following processes decreases population density ? | Both B and C |
| Question 27: Which of the following was used to control the cactus that had been introduced in Australia ? | moth |
| Question 28: What is lichen an example of ? | Mutualism |
| Question 29: Which of the following is one of the most resistant organic materials known? | Sporopollenin |
| Question 30: Which of the following cells is present in pollen grain of angiospermic plants ? | Both A and B |
| Question 31: In which of the following seeds is perisperm not found ? | Wheat |
| Question 32: Which of the following seeds has more than one embryo ? | All of these |
| Question 33: What is cotyledon called in grass family ? | Scutellum |
| Question 34: Which cell of the embryo sac becomes primary endctriple fusion ? | central cell |
| Question 35: Which of the following plays an important role in guiding the poller tube into the synergids ? | Filiform apparatus |
| Question 36: Which of the following cells are found in seminiferous tubules ? | Both A and C |
| Question 37: After how many months of pregnancy does the limbs and digits of foetus develop ? | 2 months |
| Question 38: Which of. the following placental hormones is produced during pregnancy ? | all of these |
| Question 39: In which structure of sperm are the enzymes present which help in fertilisation of the ovum ? | Acrosome |
| Question 40: Which of the following cells is haploid ? | Secondary oocyte |
| Question 41: What is the main role of large amount of progesterone secreted by corpus luteum ? | maintenance of endometrium of uterus |
| Question 42: What is it called when an embryo having more than eight blastomeres is transferred to the uterus for development ? | Intrauterine Transfer |
| Question 43: Which of the following is/are responsible for pneumonia in humans ? | both A and C |
| Question 44: What type of organism is the pathogen responsible for malaria ? | porotzoa |
| Question 45: Which of the following diseases is/are transmitted by insect vectors ? | Both B and C |
| Question 46: What kind of barrier is the interferon secreted by virus infected cells ? | cytokine barrier |
| Question 47: Which of the following cells are responsible for humoral immune response ? | B-lymphocytes |
| Question 48: What is taken by the patient to stop graft rejection ? | Immunosuppressant |
| Question 49: Which of the following are primary lymphoid organs ? | bone marrow and the thymus |
| Question 50: Which of the following viruses has reverse transcripta | HIV |
| Question 51: Which of the following drugs interferes with t dopamine ? | Cocaine |
| Question 52: Which vitamin content increases due to conversion of curd ? | Vitamin B12 |
| Question 53: Which of the following is the blood cholesterol lowering | Statin |
| Question 54: which of the following pair is incorrect? | Butyric acid - Produced by fungus |
| Question 55: Which of the following cyanobacteria fixes atmospheric nitrogen ? | all of these |
| Question 56: With the help of what are butterfly caterpillars controlled | Bacillus thuringiensis |
| Question 57: Who of the following scientists observed that restriction endonuclease can cut DNA strands in a particular shape ? | Herbert Boyer |
| Question 58: Cutting DNA at a specific site is made possible by which eøzy | Restriction endonuclease |
| Question 59: In which of the following is the large volume of culture processed to produce appreciable quantities of products ? | bioreactor |
| Question 60: The base pillar of both strands of DNA double helix is made of | Sugar - Phosphate - Nitrogenous base |
| Question 61: What is essential for occurrence of the same kind of 'sticky DNA fragments ? | To cut DNA by the same restriction endonuclease |
| Question 62: During gel electrophoresis, fragments of DNA move towards which electrode ? | Anode |
| Question 63: Which of the following is the sequence from where replication starts in cloning vector ? | ori |
| Question 64: DNA cannot pass through cell membrane because DNA is______molecule. | hydrophobic |
| Question 65: Themrostable DNA polymerase used in PCR is isolated from which bacteria ? | Thermus aquaticus |
| Question 66: Why does Bt toxin protein not kill the Bacillus ? | Bt toxin protein exists as inactive protoxins |
| Question 67: Which technique was used to prevent infection of tobacco plants from Meloidegyne incognitia tapeworm ? | RNA interference |
| Question 68: Gene therapy was first used to remove the deficiency of which of the following enzymes ? | Adenosine Deaminase (ADA). |
| Question 69: In 1997, an American company.... | Semi-dwarf variety of rice |
| Question 70: Which human protein is found in milk of the first transgenic cow-Rosie ? | Alpha lactalbumin |
Bihar Board 2026 Class 12th Biology: Question Paper Analysis
Students can access the Bihar Board 2026 Class 12th Biology Exam Analysis from the table below.
| Particulars | Details |
| Bihar Board 2026 Class 12th Biology Overall Difficulty Level | Easy to Moderate |
| Was the Paper Lengthy? | Yes |
| Number of Good Attempts | 50-55+ |
| Important Topics Asked | to be updated |
The Bihar Board 2026 Class 12th Biology Unofficial Answer Key is prepared by the subject-experts. Students are advised to use the above unofficial answer key to evaluate their performances. Unofficial answer keys are typically released by private coaching institutes and subject experts within a few hours of the exam's conclusion to help students estimate their scores.