Class 12 CBSE Biology Answer Key 2025 (Available): Set-wise unofficial keys PDF download
For the exam on March 25, 2025, Class 12 CBSE Biology Answer Key 2025 has been provided here. The unofficial CBSE Class 12 Biology Answer Key 2025 PDF for all sets can be accessed below.
Class 12 CBSE Biology Answer Key 2025: To help in estimating scores, answer keys have been made available for the CBSE Class 12 Biology Answer 2025 exam conducted on March 25, 2025. Immediately after the exam, concludes at 1:30 pm, our experts have been providing answers for answers for Section A including multiple choice questions and assertion reason questions. This page contains the correct answers for every exam set, allowing students to check their answers against the right ones. By using this guide, students can see where they did well and which areas they might need to review more. Looking over these answer keys not only aids in figuring out the correct answers but also helps deepen their understanding of the subject.
Also Read | Class 12 CBSE Result Expected Release Date 2025
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| CBSE Class 12 Computer Science Question Bank 2025 | CBSE Class 12 Computer Science Weightage 2025 |
| CBSE Class 12 Computer Science Exam 2025 Most Repeated Questions | |
Class 12 CBSE Biology Unofficial Answer Key 2025
Check out the CBSE Class 12 Biology unofficial answer key 2025 for MCQs from both Section A and Section B here in the given tables:
Section A - Multiple Choice Questions (QP Code : 57/5/2)
| Question Number | Questions | Correct Answers | ||||||||||
| 1. | The region of chromatin that are actively transcribed are thought to be : | Euchromatin. | ||||||||||
| 2. | Given below are few statements with reference to the ovaries of the human femalereproductive system: (i) It is 2-4 cm in length and is connected to the pelvic wall by tendons. (ii) It is covered by a thin epithelium which encloses the ovarian stroma. (iii) The stroma is divided into a peripheral medulla and an inner cortex. (iv) The ovaries are the primary female sex organs that produce the female gamete (ovum). (v) Ovaries are located one on each side of the lower abdomen. Choose the option with all true statements from the given options: | (ii), (iv) and (v) | ||||||||||
| 3. | The approach of sequencing the whole set of genome, including all the coding and non-coding sequences in HGP is: | Sequence Annotation. | ||||||||||
| 4. | In the pedigree chart given below, what should be the genotype of the indicated member? | XY | ||||||||||
| 5. | The lobed organ located near the heart and beneath the breast bone in humans is ___ | Thymus | ||||||||||
| 6. | Unisexuality of flowers prevents which process? | Autogamy, but not Geitonogamy | ||||||||||
| 7. | Which of the following combinations is a correct example of convergent evolution in Placental mammals and Australian marsupials?
| Tasmanian tiger cat - Anteater | ||||||||||
| 8. | Isolation of DNA from a bacterial cell can be achieved by using: | Lysozyme | ||||||||||
| 9. | Match the terms in Column-I with their description in Column-II and choose the correct option. Column-I (Terms) a. Dominance b. Codominance c. Pleiotropy d. Polygenic inheritance Column-II (Descriptions) (i) Many genes govern a single character. (ii) In a heterozygote organism, only one allele expresses itself. (iii) In a heterozygous organism, both alleles express themselves fully. (iv) A single gene influences many characters. | a-(ii), b-(i), c-(iv), d-(iii) | ||||||||||
| 10. | Which enzyme(s) will be produced in a bacterial cell in which 'UAG' is inserted in the lac-y gene' due to mutation? | β-galactosidase. | ||||||||||
| 11 | Large scale industrial production of citric acid for human welfare is done using the microbe: | Aspergillus sp | ||||||||||
| 12 | In a DNA, percentage of thymine is 20. What is the percentage of Guanine? | 60% |
Section A - Assertion and Reason
| Question Number | Questions | Correct Answers |
| 13 | Assertion (A): Gene pairs present on the same chromosome may be tightly linked or loosely linked. Reason (R): Frequency of recombination between gone pairs on dittorent chromosomes as a mensure of the distance between genes can be used for 'mapping' their position on the chromosomes. | Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A) |
| 14 | Assertion (A): Cu-T, Cu-7 and LNG-20 are the most widely used copper-relensing IUDs. Reason (R): Cu-ions in IUDs effectively suppress sperm motility and the fertilising capacity of sperms | Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A) |
| 15 | Assertion (A): To generate only a part of the plant from a cell is totipotency. Reason (R): Suitable special nutrient media and sterile conditions are required in 'in vitro' conditions for the division of cells in explants. | Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A) |
| 16 | Assertion (A): Lymphocytes arise from bone marrow and present in the blood and lymph and serve as natural killer cells. Reason (R): Lymphocytes migrate to thymus, where they develop into T-cells and begin to mature. | Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A) |
Section A - Multiple Choice Questions (QP Code : 57/1/1)
| Question Number | Questions | Correct Answers |
| 1 | A man whose father was colour-blind marries a woman who had a colour blind mother and normal father. What percentage of male children of this couple will be colour-blind"? | 50% |
| 2 | GEAC stands for | Genetic Engineering Approval Committee |
| 3 | Match the items in Column-A with that of Column B Column-A (i) Lady bird beetle (ii) Mycorrhiza (iii) Biological control (iv) Biogas Column-B (a) Methanobacterium (b) Trichoderma (c) Aphids (d) Glomus Choose the option that matches the items of Column A with that of B correctly | (c) (d) (b) (a) |
| 4 | The process of mineralization by microorganisms help in the release of | inorganic nutrients from detritus and formation of humus |
| 5 | Transplantation of tissues/organs to some patients often fails due to rejection of such tissues/organs by the body of the patient. Which type of immune response is responsible for such rejections? | Cell mediated immune response |
| 6 | Match the following items of Column I with that of Column-II Column-I (a) Trophoblast (b) Implantation (c) Inner cell mass (d) Morula Column-II (i) Embedding of blastocyst in the endometrium (ii) Group of cells that would differentiate as embryo (iii) Embryo with 8-16 blastomeres (iv) Outer layer of blastocyst Choose the option that matches Column-l with Column-II correctly | (iv) (i) (ii) (iii) |
| 7 | The diagram given below shows labelling of four parts of a dicot embryo during its development as P. Q. R and S. Choose the option that indicates correcte labelling P. Q. R' and 'S' of P. Q. R' and 'S' of embryo in different stages of its development: | P: Zygote Q: Suspensor R: Cotyledon S: Plumule. |
| 8 | Amplification of gene of interest by using DNA polymerase may go upto | 1 billion times |
| 9 | The sequence of nitrogenous bases in a segment of a coding strand of DNA is 5AATGCTAGGCAC-3. Choose the option that shows the correct sequence of nitrogenous bases in the mRNA transcribed by the DNA | 5 AAUGCUAGGCAC-3 |
| 10 | How many pollen grains and ovules are likely to be formed in the anther and the ovary of an angiosperm bearing 50 microspore mother cells and 50 megaspore mother cells respectively? | 200,50 |
| 11 | Evolution of modern man involves the following man-like primates Choose the correct series of human evolution | Australopithecines→ Homo erectus→ Neanderthal →Homo sapiens |
| 12 | RNA interference (RNA1) helps in making tobacco-plant resistant to a nematode (Meloidegyne incognitia) Choose the correct option that shows how RNAi is achieved | Preventing the process of translation of mRNA of the nematode |
Section A - Assertion and Reason
| Question Number | Questions | Correct Answers |
| 13 | Assertion (A): Saheli is the World's first non-steroidal oral contraceptive pill. Reason (R): It has been developed by National Institute of Immunology, New Delhi | (A) is true, but (R) is false. |
| 14 | Assertion (A): One of the property of genetic code is degeneracy Reason (R): Some amino acids can be coded by more than one codon | Both (A) and (R) are true and (R) is the correct explanation of (A) |
| 15 | Assertion (A): A bioreactor provides the optimal conditions for achieving the desired product by providing optimum growth conditions. Reason (R): The most commonly used bioreactors are of stirring type. | Both (A) and (R) are true, but (R) is not the correct explanation of (A). |
| 16 | Assertion (A): When the two genes in a dihybrid cross are situated on the type same chromosome, the proportion of parental gene combinations is much higher than non-parental type Reason (R): Higher parental gene combinations can be attributed to crossing over between two genes | (A) is true, but (R) is false. |
Section A - Multiple Choice Questions (QP Code : 57/6/3)
| Question Number | Questions | Correct Answers |
| 1 | Cistron is a segment of DNA coding for a : | mRNA only |
| 2 | In a pedigree chart, if two unaffected individuals have a child with the trait, what is the most likely mode of inheritance for this trait? | Autosomal recessive |
| 3 | If a natural population with 200 individuals is in Hardy-Weinberg equilibrium for a gene with two alleles A and a, with the gene frequency of allele A of 0-8, the genotype frequency of Aa will be: | 0.32 |
| 4 | Select the statements that are true for a typical monocotyledonous embryo from the given options. (i) Scutellum is present towards the centre of the embryonal axis. (ii) Embryonal axis of the lower end has radicle and root cap covered by coleoptile. (iii) The portion of embryonal axis above the level of attachment of scutellum is epicotyl. (iv) Shoot apex and few leaf primordia of embryo are enclosed in a hollow foliar structure. Choose the correct answer from the following: | (iii) and (iv) |
| 5 | Given below are a few statements with reference to the human sperm. (i) Sperm head contains a large nucleus and a lot of cytoplasm. (ii) Mitochondria in the middle piece of a sperm provides ATP for the sperm motility. (iii) Posterior part of the sperm head is covered by acrosome. (iv) Spermatids undergo maturation into spermatozoa by the process of spermiogenesis. (v) Acrosomal secretions help in the entry of the sperm into the ovum at the time of fertilization. Choose the option with all true statements from the given options: | (ii), (iv) and (v) |
| 6 | A normal couple produces half the sons as haemophilic and half the daughters as carriers. Choose the option that correctly indicates the chromosome on which the gene for this trait is located. | One X-chromosome of mother |
| 7 | If the sequence of bases in DNA is ATTCGATG, then the sequence of bases in the transcript will be: | UAAGCUAC |
| 8 | In a translational unit UTRs are present at: | 5' end (before start codon) and 3' end (after stop codon) |
| 9 | The lymphoid organ located within the lining of respiratory, digestive and urinogenital tract is: | MALT |
| 10 | Land reptiles which went back into water about 200 mya to evolve into fish-like reptiles were: | Ichthyosaurus |
| 11 | Certain viruses used as biological control agents belong to the genus: | Nucleopolyhedrovirus |
| 12 | Thee cloning site present in the ampicillin resistance gene of E. coli coliing vector pBR322 is: | Pst I |
Section A - Assertion and Reason
| Question Number | Questions | Correct Answers |
| 13 | Assertion (A): An antibody is a protein molecule made by the lymphocytes. Reason (R): An antibody binds to a specific foreign antigen and neutralizes its odd effects. | Both (A) and (R) are true and (R) is the correct explanation of (A) |
| 14 | Assertion (A): Male contraceptive 'Nirodh' works on the principle of avoiding chances of ovum and sperm meeting. Reason (R): It is made of thin rubber/latex sheath and is used to cover the ochis before coilus. | Both (A) and (R) are true and (R) is the correct explanation of (A) |
| 15 | Assertion (A): In dihybrid crosses involving sex-linked genes in Drosophila generation of non-parental gene combinations are observed. Reason (R): Two genes present on different chromosomes show linkage RX and recombination in Drosophila. | Assertion (A) is true, but Reason (R): is false. |
| 16 | Assertion (A): Isolated single cells can be fused to produce somatic hybrids. Reason (R): Cells selected for somatic hybridisation have desirable characters | Both (A) and (R) are true and (R) is the correct explanation of (A) |
Section A - Multiple Choice Questions (QP Code : 57/5/1)
| Question Number | Questions | Correct Answers |
| 1 | The histone core in a nucleosome of chromatin thread is a/an: | octamer |
| 2 | Given below are few statements with reference to the uterus in the female reproductive system: (i) The myometrium exhibits strong contractions during the delivery of the baby. (ii) The uterus opens into the cervix through a narrow opening is called vagina. (iii) The cavity of the cervix and the vagina forms the birth canal. (iv) The outermost layer of uterus is a thin membranous perimetrium. (v) The uterus is supported by tendons attached to the pelvic wall. Choose the option with all true statements from the given options | (i), (iii) and (iv) |
| 3 | During the process of transcription, after binding to a promoter, RNA polymerase catalyses and makes the bases in the template strand of DNA available for base pairing, with the bases of: | Ribonucleoside triphosphate |
| 4 | Which of the following is not an example of aneuploidy | Phenylketonuria |
| 5 | Colostrum secreted by the mother's mammary glands in a human female during the initial days of lactation is rich in antibody: | IgA |
| 6 | Select the statements that are true for pollination mechanism in flowering plants from the given options. (i) In Vallisneria, the female flowers are pollinated by pollen grains inside the water. (ii) In Zostera, pollen grains are released on the surface of water. (iii) In most of the water-pollinated species, pollen grains are covered by a mucilaginous coating. (iv) Pollination by water is quite rare and limited to about 30 Choose the correct answer: | (iii) and (iv) |
| 7 | Which of the following combinations is a correct example of convergent evolution in Australian marsupials and Placental mammals? Australian Marsupials (A) Lemur (B) Tasmanian tiger cat (C) Bobcat (D) Numbat Placental Mammals Spotted cuscus Anteater Lemur Anteater | Lemur-Spotted cuscus |
| 8 | Isolation of DNA from a fungal cell can be achieved by using __ | Chitinase |
| 9 | During a monohybrid cross involving a tall pea plant, with a drawf pea plant, the offspring populations were tall and dwarf in eaual ratio. Find out the genotype of parent pea plants. | Tt x tt |
| 10 | What would happen if a gene encoding a polypeptide of 50 aminoacids, 25th Codon (UAU) is mutated to "UAA"? | A polypeptide of 24 amino acids will be formed. |
| 11 | Large scale industrial production of Butyric acid for human welfare is done using the microbe: | Clostridium sp |
| 12 | The correct depiction of the centrifugation step of the experiment conducted by Alfred Hershey and Martha Chase on using radioactive labelled phages to prove that DNA is the genetic material is: |
Section A - Assertion and Reason
| Question Number | Questions | Correct Answers |
| 13 | Assertion (A): To generate only a part of the plant from a cell is totipotency. Reason (R): Suitable special nutrient media and sterile conditions are required in in vitro' conditions for the division of cells in explants. | Assertion (A) is false, but Reason (R) is true. |
| 14 | Assertion (A): Biogas plants are more often built in rural areas. Reason (R): The excreta or gobar of cattle is rich in Methanobacterium | Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A). |
| 15 | Assertion (A): Gene pairs present on the same chromosome may be tightly linked or loosely linked. Reason (R): Frequency of recombination between gone pairs on different chromosomes as a mensure of the distance between genes can be used for 'mapping' their position on the chromosomes. | Assertion (A) is true, but Reason (R) is false. |
| 16 | Assertion (A): Cu-T, Cu-7 and LNG-20 are the most widely used copper-relensing IUDs. Reason (R): Cu-ions in IUDs effectively suppress sperm motility and the fertilising capacity of sperms | Assertion (A) is false, but Reason (R) is true. |
Class 12 CBSE Biology 2025: Exam Analysis Link
Apart from the CBSE Class 12 Biology unofficial answer key, the candidates can find out the exam analysis here:
Class 12 CBSE Subject-Wise Answer Key 2025 |
| Subject Name | Answer Key Links |
|---|---|
| English Core | Class 12 CBSE English Answer Key 2025 |
| Chemistry | Class 12 CBSE Chemistry Answer Key 2025 |
| Physics | Class 12 CBSE Physics Answer Key 2025 |
| Mathematics | Class 12 CBSE Mathematics Answer Key 2025 |
| Physical Education | Class 12 CBSE Physical Education Answer Key 2025 |
| Entrepreneurship | Class 12 CBSE Entrepreneurship Answer Key 2025 |
| Business Studies | Class 12 CBSE Business Studies Answer Key 2025 |
| Geography | Class 12 CBSE Geography Answer Key 2025 |
| Hindi Core | CBSE Class 12 Hindi Answer Key 2025 |
| Economics | Class 12 CBSE Economics Answer Key 2025 |
| Political Science | Class 12 CBSE Political Science Answer Key 2025 |
| Accountancy | Class 12 CBSE Accountancy Answer Key 2025 |
Class 12 CBSE Toughest and Easiest Subject 2025 |
| Parameters | Links |
|---|---|
| Toughest Subject | Toughest Subject of CBSE Class 12 Exams 2025 |
| Easiest Subject | Easiest Subject of CBSE Class 12 Exams 2025 |
Class 12 CBSE Biology Answer Key 2025 Live Updates
Mar 25, 2025 11:00 PM IST
Class 12 CBSE Biology Answer Key 2025: Question 10
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 10: How many pollen grains and ovules are likely to be formed in the anther and the ovary of an angiosperm bearing 50 microspore mother cells and 50 megaspore mother cells respectively?
Answer: 200,50
Mar 25, 2025 10:40 PM IST
CBSE Class 12 Biology Answer Key 2025: Question 9
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 9: The sequence of nitrogenous bases in a segment of a coding strand of DNA is 5AATGCTAGGCAC-3. Choose the option that shows the correct sequence of nitrogenous bases in the mRNA transcribed by the DNA
Answer: 5 AAUGCUAGGCAC-3
Mar 25, 2025 10:20 PM IST
Class 12 CBSE Biology Answer Key 2025: Question 8
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 8: Amplification of gene of interest by using DNA polymerase may go upto
Answer: 1 billion times
Mar 25, 2025 10:00 PM IST
CBSE Class 12 Biology Answer Key 2025: Question 6
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 6: Match the following items of Column I with that of Column-II
Column-I
(a) Trophoblast
(b) Implantation
(c) Inner cell mass
(d) Morula
Column-II
(i) Embedding of blastocyst in the endometrium
(ii) Group of cells that would differentiate as embryo
(iii) Embryo with 8-16 blastomeres
(iv) Outer layer of blastocyst
Choose the option thatAnswer: (iv) (i) (ii) (iii)
Mar 25, 2025 09:40 PM IST
Class 12 CBSE Biology Answer Key 2025: Question 5
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 5: Transplantation of tissues/organs to some patients often fails due to rejection of such tissues/organs by the body of the patient. Which type of immune response is responsible for such rejections?
Answer: Cell mediated immune response
Mar 25, 2025 09:20 PM IST
CBSE Class 12 Biology Answer Key 2025: Question 4
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 4: The process of mineralization by microorganisms help in the release of ____
Answer: inorganic nutrients from detritus and formation of humus
Mar 25, 2025 09:00 PM IST
Class 12 CBSE Biology Answer Key 2025: Question 3
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 3:
Match the items in Column-A with that of Column B
Column-A
(i) Lady bird beetle
(ii) Mycorrhiza
(iii) Biological control
(iv) Biogas
Column-B
(a) Methanobacterium
(b) Trichoderma
(c) Aphids
(d) Glomus
Choose the option that matches the items of Column A with that of B correctlyAnswer: (c) (d) (b) (a)
Mar 25, 2025 08:40 PM IST
CBSE Class 12 Biology Answer Key 2025: Question 2
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 2: GEAC stands for
Answer: Genetic Engineering Approval Committee
Mar 25, 2025 08:20 PM IST
Class 12 CBSE Biology Answer Key 2025: Section A - Multiple Choice Questions (QP Code : 57/1/1)
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 1: A man whose father was colour-blind marries a woman who had a colour blind mother and normal father. What percentage of male children of this couple will be colour-blind"?
Answer: 50%Mar 25, 2025 08:00 PM IST
CBSE Class 12 Biology Answer Key 2025: Question 16
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 16:
Assertion (A): When the two genes in a dihybrid cross are situated on the type same chromosome, the proportion of parental gene combinations is much higher than non-parental type
Reason (R): Higher parental gene combinations can be attributed to crossing over between two genesAnswer: (A) is true, but (R) is false.
Mar 25, 2025 07:40 PM IST
Class 12 CBSE Biology Answer Key 2025: Question 15
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 15:
Assertion (A): A bioreactor provides the optimal conditions for achieving the desired product by providing optimum growth conditions.
Reason (R): The most commonly used bioreactors are of stirring type.
Answer: Both (A) and (R) are true, but (R) is not the correct explanation of (A).
Mar 25, 2025 07:20 PM IST
CBSE Class 12 Biology Answer Key 2025: Question 14
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 14:
Assertion (A): One of the property of genetic code is degeneracy
Reason (R): Some amino acids can be coded by more than one codonAnswer: Both (A) and (R) are true and (R) is the correct explanation of (A)
Mar 25, 2025 07:00 PM IST
Class 12 CBSE Biology Answer Key 2025: Section A - Assertion and Reason
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 13: Assertion (A): Saheli is the World's first non-steroidal oral contraceptive pill.
Reason (R): It has been developed by National Institute of Immunology, New DelhiAnswer: (A) is true, but (R) is false.
Mar 25, 2025 06:40 PM IST
CBSE Class 12 Biology Answer Key 2025: Question 11
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 12: In DNA, the percentage of thymine is 20. What is the percentage of Guanine?
Answer: 60%
Mar 25, 2025 06:20 PM IST
Class 12 CBSE Biology Answer Key 2025: Question 11
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 11: Large scale industrial production of citric acid for human welfare is done using the microbe:
Answer: Aspergillus sp
Mar 25, 2025 06:00 PM IST
Class 12 CBSE Biology Answer Key 2025: Question 10
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 10: Which enzyme(s) will be produced in a bacterial cell in which 'UAG' is inserted in the lac-y gene' due to mutation?
Answer: β-galactosidase.
Mar 25, 2025 05:40 PM IST
CBSE Class 12 Biology Answer Key 2025: Question 9
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 9:
Match the terms in Column-I with their description in Column-II and choose the correct option.
Column-I
(Terms)a. Dominance
b. Codominance
c. Pleiotropy
d. Polygenic inheritanceColumn-II
(Descriptions)
(i) Many genes govern a single character.
(ii) In a heterozygote organism, only one allele expresses itself.
(iii) In a heterozygous organism, both alleles express themselves fully.
(iv) A single gene influences many characters.Answer: a-(ii), b-(i), c-(iv), d-(iii)
Mar 25, 2025 05:20 PM IST
Class 12 CBSE Biology Answer Key 2025: Question 8
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 8: Isolation of DNA from a bacterial cell can be achieved by using:
Answer: Lysozyme
Mar 25, 2025 05:00 PM IST
Class 12 CBSE Biology Answer Key 2025: Question 7
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 7: Which of the following combinations is a correct example of convergent evolution in Placental mammals and Australian marsupials?
Placental Mammals
(A) Anteater(B) Numbat
(C) Tasmanian tiger cat
(D) Lemur
Australian Marsupials
Lemur
Bobent
Anteater
Spotted cuscusAnswer: Tasmanian tiger cat - Anteater
Mar 25, 2025 04:45 PM IST
CBSE Class 12 Biology Answer Key 2025: Question 6
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 6: Does the unisexuality of flowers prevent this process?
Answer: Autogamy, but not Geitonogamy
Mar 25, 2025 04:30 PM IST
Class 12 CBSE Biology Answer Key 2025: Question 5
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 5: The lobed organ located near the heart and beneath the breast bone in humans is ___
Answer: Thymus
Mar 25, 2025 04:15 PM IST
CBSE Class 12 Biology Answer Key 2025: Question 4
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 4: In the pedigree chart given below, what should be the genotype of the indicated member?
Answer: XY
Mar 25, 2025 04:00 PM IST
Class 12 CBSE Biology Answer Key 2025: Question 3
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 3: The approach of sequencing the whole set of genome, including all the coding and non-coding sequences in HGP is:
Answer: Sequence Annotation.
Mar 25, 2025 03:45 PM IST
Class 12 CBSE Biology Answer Key 2025: Question 2
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 2:
Given below are few statements with reference to the ovaries of the human female reproductive system:
(i) It is 2-4 cm in length and is connected to the pelvic wall by tendons.
(ii) It is covered by a thin epithelium which encloses the ovarian stroma.
(iii) The stroma is divided into a peripheral medulla and an inner cortex.
(iv) The ovaries are the primary female sex organs that produce the female gamete (ovum).
(v) Ovaries are located one on each side of the lower abdomen.
Choose the option with all true statements from the given options:Answer: (ii), (iv) and (v)
Mar 25, 2025 03:30 PM IST
CBSE Class 12 Biology Answer Key 2025: Multiple Choice Questions (QP Code : 57/5/2)
Aspirants can check the questions with solutions below as per the class 12 CBSE Biology Answer Key 2025.
Question 1: The region of chromatin that are actively transcribed are thought to be :
Answer: Euchromatin.
Mar 25, 2025 03:15 PM IST
Class 12 CBSE Biology Answer Key 2025: Exam Analysis
The below-highlighted table shows the CBSE Class 12 Biology exam analysis in depth:
Parameter
Exam Analysis 2025
Overall difficulty level of the paper
Moderate
Difficulty Level of Section A
Easy
Difficulty Level of Section B
Moderate
Difficulty Level of Section C
Easy to Moderate
Difficulty Level of Section D
Moderate
Difficulty Level of Section E
Easy to Moderate Expected Good Score
50+
Lengthiest Question (If any)
No
Time-Consuming Section (If any)
No
Mar 25, 2025 03:00 PM IST
Class 12 CBSE Biology Answer Key 2025: Overall difficulty level of the paper
According to initial feedback from students, the overall difficulty level of the CBSE Class 12 Biology paper was considered 'Easy to Moderate'.
Mar 25, 2025 02:45 PM IST
CBSE Class 12 Biology Answer Key 2025: Student Reviews
Discover the insights and opinions gathered from students about the CBSE Class 12 Biology exam analysis for 2025 in the section highlighted below.
- Most students felt the paper was 'Easy to Moderate' although MCQs were Easy.
- Some students shared that Section B was moderate and case-based questions were slightly tricky.
- Students who received Set 3 found it to be more difficult compared to the other sets.
Mar 25, 2025 02:30 PM IST
Class 12 CBSE Biology Answer Key 2025: Discrepancies
If there are any discrepancies or uncertainties, students should reach out to their school officials or contact CBSE directly.
Mar 25, 2025 02:15 PM IST
Class 12 CBSE Biology Answer Key 2025: Answer Keys Soon
The answer key solutions for Class 12 CBSE Biology 2025 will be provided by our subject experts shortly. Please keep refreshing the page for updates!
Mar 25, 2025 02:00 PM IST
Class 12 CBSE Biology Answer Key 2025: How to Check Unofficial Answer Key?
As soon as the test is over, the CollegeDekho Team will compile the Class 12 CBSE Biology Answer Key 2025 from all of the tutoring centres and subject matter specialists.
Mar 25, 2025 01:45 PM IST
Class 12 CBSE Biology Answer Key 2025: Unofficial Answer Key 2025 include all sets?
Yes, answers to every question paper set will be available in the Class 12 CBSE Biology 2025 unofficial answer key.
Mar 25, 2025 01:30 PM IST
Class 12 CBSE Biology Answer Key 2025: Exam Over
Class 12 CBSE Biology 2025 exam has been concluded at 1:30 pm. Invigilators are now collecting the question papers.
Mar 25, 2025 01:10 PM IST
Class 12 CBSE Biology Answer Key 2025: Why to refer to answer keys?
It enables students to determine their approximate grades, examine errors, and comprehend the proper method for responding to inquiries.
Mar 25, 2025 12:50 PM IST
Class 12 CBSE Biology Answer Key 2025: What are the passing marks?
To pass, students must receive at least 35% on both the theory and practical tests.
Mar 25, 2025 12:30 PM IST
Class 12 CBSE Biology Answer Key 2025: Answer Key by Coaching Institutes
As soon as the test is over, the various coaching centres will provide the unauthorised CBSE Class 12 Biology Answer Key 2025, which will be available on the website below.
Mar 25, 2025 12:10 PM IST
Class 12 CBSE Biology Answer Key 2025: Is there any Negative Marking
No, there is no negative marking for incorrect responses for CBSE Class 12 board exam 2025.
Mar 25, 2025 11:50 AM IST
Class 12 CBSE Biology Answer Key 2025: Can I Raise Objections?
Students are unable to object because the answer key is not official. They can talk to their teachers about differences, though.
Mar 25, 2025 11:30 AM IST
Class 12 CBSE Biology Answer Key 2025: Does CBSE issue official answer key?
An official answer key for the Class 12 exams has not yet been released by CBSE. Students can, however, use unofficial keys as a guide.
Mar 25, 2025 11:10 AM IST
Class 12 CBSE Biology Answer Key 2025: Will unofficial answer key be accurate?
Subject specialists and educators create the unofficial CBSE 12 Biology 2025 answer key. Despite being mostly correct, there might be a few small variations.
Mar 25, 2025 10:50 AM IST
Class 12 CBSE Biology Answer Key 2025: Release Date and Time
Our Collegedekho experts will provide Class 12 CBSE Biology Answer Key 2025 soon after the conclusion of the test at 1:30 pm.
Mar 25, 2025 10:30 AM IST
Class 12 CBSE Biology Answer Key 2025: Exam Begins
CBSE Class 12 Biology2025 exam has begun today at 10:30 am.
Mar 25, 2025 10:10 AM IST
Class 12 CBSE Biology Answer Key 2025: Most Repeated Question 10
The length of a DNA molecule in a typical mammalian cell is calculated to be approximately 2.2 meters. How is the packaging of this long molecule done to accommodate it within the nucleus of the cell.
Mar 25, 2025 09:50 AM IST
Class 12 CBSE Biology Answer Key 2025: Most Repeated Question 9
Differentiate between the following :
(i) Perisperm and Pericarp
(ii) Syncarpous pistil and Apocarpous pistil
(iii) Plumule and Radicle
Mar 25, 2025 09:30 AM IST
Class 12 CBSE Biology Answer Key 2025: Most Repeated Question 8
Name the type of human cell HIV attacks at its entry into the body. Explain the events that occur in the cell which further lead to cause immunodeficiency syndrome.
Mar 25, 2025 09:15 AM IST
Class 12 CBSE Biology Answer Key 2025: Most Repeated Question 7
Expand IUD (b) Why is hormone releasing IUD considered a good contraceptive to space children?
Mar 25, 2025 09:00 AM IST
Class 12 CBSE Biology Answer Key 2025: Most Repeated Question 6
A human being suffering from Down’s syndrome show trisomy of 21st chromosome. Mention the cause of this chromosomal abnormality.
Mar 25, 2025 08:45 AM IST
Class 12 CBSE Biology Answer Key 2025: Most Repeated Question 5
Mention two functions of codon AUG.
Mar 25, 2025 08:30 AM IST
Class 12 CBSE Biology Answer Key 2025: Most Repeated Question 4
Which one of the following processes results in the production of recombinants in future generations?
(i) Mutation (ii) Independent assortment during meiosis (iii) Independent assortment during meiosis II (iv) Crossing over of bivalents
(a) (iv) only
(b) (ii) and (iv)
(c) (i), (ii) and (iii)
(d) (i), (ii), (iii) and (iv)
Mar 25, 2025 08:15 AM IST
Class 12 CBSE Biology Answer Key 2025: Most Repeated Question 3
Assertion (A): A patient of ADA deficiency undergoing treatment for gene therapy requires periodic infusion of genetically engineered lymphocytes.
Reason (R): Lymphocytes are immortal.
Mar 25, 2025 08:00 AM IST
Class 12 CBSE Biology Answer Key 2025: Most Repeated Question 2
Mention any two significant roles predation play in nature.
Mar 25, 2025 07:45 AM IST
Class 12 CBSE Biology Answer Key 2025: Most Repeated Question 1
Since a few hours are left for the test, practice the most repeated questions here.
1. Name the type of human cell HIV attacks at its entry into the body. Explain the events that occur in the cell which further lead to cause immunodeficiency syndrome.
Mar 25, 2025 07:30 AM IST
Class 12 CBSE Biology Answer Key 2025: Exam Today
Today, March 25, 2025, the CBSE Class 12 Biology test will be administered by the Central Board of Secondary Education (CBSE).