Score better in Biology with these CBSE Class 12 MCQs, ready for 2026-27. Built chapter by chapter, they help Class 12 students get comfortable with the current exam pattern and sharpen problem-solving.
How Biology MCQs Help Class 12 Students
- Answers are explained clearly for every Biology question, so the reasoning actually makes sense.
- Matched closely to the 2026 CBSE Biology textbook and current guidelines.
- Includes Class 12 Assertion-Reasoning, Case-based, and Fill-in-the-blanks formats, all built for Biology.
- Neatly organized by chapter, so you can test your grip on each Biology topic one at a time.
Class 12 Biology Chapter-wise MCQ Question Bank
Access the latest 2026-27 question sets for Biology below. These MCQs are a solid way to check your own understanding, and spot weak areas before your exams.
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Quick Practice - Try a Few Questions First Pick a chapter below, answer a few questions instantly, then jump to the full set list for more. Q1.In a typical angiosperm flower, the male reproductive part is called the: Answer: (b) Androecium. It is made up of stamens, and each stamen carries an anther where pollen grains are actually produced.
Q2.Double fertilization in flowering plants was first described by: Answer: (b) Nawaschin. He reported this process back in 1898. One male gamete fuses with the egg, and the other fuses with the two polar nuclei.
Q3.The fusion of a male gamete with the two polar nuclei, forming a triploid nucleus, is called: Answer: (b) Triple fusion. This gives rise to the primary endosperm nucleus, which later develops into the tissue that nourishes the growing embryo.
Q4.Pollination between two flowers on the same plant is known as: Answer: (b) Geitonogamy. Even though pollen moves between two different flowers, both belong to the same plant, so genetically it behaves like self-pollination.
Q5.A fruit that develops without fertilization taking place is called a: Answer: (a) Parthenocarpic fruit. Bananas are a familiar everyday example. It is part of why they do not really have noticeable seeds.
Q1.Spermatogenesis takes place inside the: Answer: (b) Seminiferous tubules. These are the tightly coiled tubes inside the testes where sperm cells are actually produced.
Q2.The hormone mainly responsible for triggering ovulation is: Answer: (b) LH. A sudden surge in LH partway through the menstrual cycle causes the mature Graafian follicle to rupture and release the egg.
Q3.Fertilization of the human egg normally takes place in the: Answer: (b) Ampullary isthmic junction of the fallopian tube. This is roughly halfway along the tube, before the fertilized egg begins its journey toward the uterus.
Q4.Which structure provides nutrition to the developing foetus? Answer: (b) Placenta. It also works as an endocrine gland during pregnancy, producing hormones such as hCG, estrogen and progesterone.
Q5.The process of expelling the foetus at the end of pregnancy is called: Answer: (b) Parturition. Signals from both the fully developed foetus and the placenta trigger the strong uterine contractions that make this happen.
Q1.Which of these is a natural method of contraception? Answer: (c) Rhythm method. It works by avoiding intercourse during the fertile period, rather than relying on any device or medication.
Q2.Tubectomy, as a surgical method of contraception, is carried out in: Answer: (b) Females. It involves cutting and sealing the fallopian tubes, so an egg can no longer meet sperm.
Q3.Amniocentesis is mainly used to detect: Answer: (b) Genetic and chromosomal disorders in the foetus. In India, using this test to determine the sex of a foetus is legally banned.
Q4.In vitro fertilization refers to fertilization that takes place: Answer: (b) Outside the body, in a laboratory. The resulting embryo is later transferred into the uterus. This technique is popularly known as the test tube baby method.
Q5.STDs such as syphilis and gonorrhoea are caused by: Answer: (b) Bacteria. Both are curable if caught and treated early, which is exactly why regular checkups matter for anyone sexually active.
Q1.Mendel's Law of Segregation states that: Answer: (a) The two alleles of a gene separate during gamete formation. Each gamete ends up with only one allele from the pair, never both together.
Q2.A cross between an individual of unknown genotype and a homozygous recessive individual is called a: Answer: (b) Test cross. It's a simple way to figure out whether an organism showing a dominant trait is homozygous or heterozygous for it.
Q3.Haemophilia is inherited as a: Answer: (b) X-linked recessive trait. That's why the condition shows up far more often in males, who only carry one X chromosome.
Q4.Down's syndrome is caused by: Answer: (b) Trisomy of chromosome 21. An affected individual carries an extra copy of chromosome 21, giving 47 chromosomes in total instead of the usual 46.
Q5.A change in the nucleotide sequence of DNA is called a: Answer: (b) Mutation. Mutations can occur naturally or be caused by external agents called mutagens, and they are the ultimate source of genetic variation.
Q1.The building blocks of DNA are called: Answer: (b) Nucleotides. Each one is made of a nitrogenous base, a sugar molecule, and a phosphate group joined together.
Q2.Which scientists proposed the double helix structure of DNA? Answer: (b) Watson and Crick. They published this structure in 1953, building heavily on X-ray diffraction data collected by Rosalind Franklin.
Q3.The process of copying genetic information from DNA into mRNA is called: Answer: (b) Transcription. This mRNA copy then carries the genetic message out of the nucleus so it can be used to build proteins.
Q4.A sequence of three nucleotides that codes for a specific amino acid is called a: Answer: (b) Codon. There are 64 possible codons but only 20 amino acids, so the genetic code is described as degenerate.
Q5.The Human Genome Project mainly aimed to: Answer: (b) Sequence the entire human DNA and identify all genes. It was completed in 2003 and remains one of the largest collaborative scientific efforts ever undertaken.
Q1.The theory of natural selection was proposed by: Answer: (b) Darwin. He argued that individuals with favourable variations survive and reproduce more successfully, gradually reshaping a population over generations.
Q2.Homologous organs are those that have: Answer: (b) Similar origin but different function. The forelimbs of a whale, a bat, and a human are a classic example, all built on the same underlying bone plan.
Q3.Analogous organs are evidence of: Answer: (b) Convergent evolution. Wings of birds and insects look and work alike but evolved completely independently of each other.
Q4.Which of these is regarded as a connecting link between reptiles and birds? Answer: (a) Archaeopteryx. It had feathers like a bird but also reptilian features such as teeth and a long bony tail.
Q5.Industrial melanism in peppered moths is often cited as an example of: Answer: (b) Natural selection in action. Darker moths became more common near industrial areas simply because soot covered trees made them harder for predators to spot.
Q1.Antibodies belong to which class of proteins? Answer: (b) Immunoglobulins. These Y-shaped proteins are made by plasma cells and are built to recognise and bind to specific antigens.
Q2.AIDS is caused by a: Answer: (b) Retrovirus. HIV uses the enzyme reverse transcriptase to convert its RNA genome into DNA once it is inside a host cell.
Q3.Which of these diseases is caused by a protozoan parasite? Answer: (b) Malaria. It's caused by Plasmodium species and spreads through the bite of an infected female Anopheles mosquito.
Q4.Cancer cells differ from normal cells mainly because they: Answer: (b) Divide uncontrollably and lose contact inhibition. This loss of normal growth control is really the defining feature of a cancer cell.
Q5.Morphine is obtained from which plant? Answer: (b) Papaver somniferum, the opium poppy. Morphine is extracted from the latex found in its unripe seed capsules.
Q1.Lactobacillus is commonly used in preparing: Answer: (b) Curd. These bacteria convert lactose in milk into lactic acid, which curdles it and also improves its nutritional value.
Q2.Which microbe is used to produce the antibiotic penicillin? Answer: (a) Penicillium notatum. Alexander Fleming's accidental discovery of this fungus's antibacterial effect led to the whole field of antibiotics.
Q3.Biogas is mainly produced through the activity of: Answer: (b) Methanogens. These are a group of archaea that break down organic waste without oxygen and release methane as a by-product.
Q4.Which of these is a biofertiliser? Answer: (a) Rhizobium. It lives in root nodules of leguminous plants and fixes atmospheric nitrogen into a form the plant can actually use.
Q5.Statins, used to lower blood cholesterol, are produced with the help of: Answer: (b) A yeast called Monascus purpureus. Statins work by blocking an enzyme the body needs in order to make cholesterol.
Q1.Restriction enzymes function by: Answer: (b) Cutting DNA at specific sequences. These sequences, called recognition sites, are usually palindromic, and this precise cutting is what makes genetic engineering possible.
Q2.A vector commonly used to carry foreign DNA into a host cell is a: Answer: (b) Plasmid. These small circular self replicating DNA molecules found in bacteria are ideal carriers, since foreign genes can be inserted into them fairly easily.
Q3.PCR stands for: Answer: (b) Polymerase Chain Reaction. It's used to make millions of copies of a specific DNA segment, starting from just a tiny original sample.
Q4.Which enzyme joins DNA fragments together during recombinant DNA technology? Answer: (b) DNA ligase. It's sometimes nicknamed the molecular glue, since it seals the gaps between DNA fragments.
Q5.Bt cotton is genetically engineered to resist: Answer: (b) Bollworm attack. The plant produces a toxin from Bacillus thuringiensis that is deadly to certain insect larvae but harmless to humans.
Q1.Golden rice is genetically modified to be rich in: Answer: (b) A vitamin A precursor called beta carotene. It was developed specifically to help tackle vitamin A deficiency in populations that rely heavily on rice as a staple food.
Q2.Human insulin produced through biotechnology is commercially sold as: Answer: (c) Both a and b. Humulin was actually the first recombinant DNA drug ever approved for human use, back in 1983.
Q3.Gene therapy was first successfully used to treat which condition? Answer: (b) Adenosine deaminase, or ADA, deficiency. This condition severely weakens the immune system, and the very first approved gene therapy trial, in 1990, targeted it directly.
Q4.Molecular diagnosis of diseases such as cancer at a very early stage often relies on: Answer: (a) ELISA and PCR. These techniques can detect extremely low concentrations of a pathogen or a specific gene, often well before symptoms appear.
Q5.Genetically modified organisms are also referred to as: Answer: (b) Transgenic organisms. They carry a gene from a completely different species that has been deliberately introduced into them.
Q1.The range of temperature within which an organism can survive and function is called its: Answer: (b) Tolerance range. Organisms able to survive across a wide range of a factor like temperature are described as eurythermal.
Q2.An interaction in which one species benefits and the other is unaffected is called: Answer: (b) Commensalism. A classic example is barnacles attached to a whale's body, which get transport and food access without harming the whale.
Q3.The logistic growth model of a population is represented by which shape of curve? Answer: (b) S shaped. Growth slows as the population nears the carrying capacity of its environment, unlike the unchecked J shaped curve.
Q4.Which of these is an example of mutualism? Answer: (b) Lichens, formed by fungi and algae living together. The fungus gets food made by the alga, and the alga gets shelter and minerals in return.
Q5.Carrying capacity of a habitat refers to: Answer: (b) The maximum population size the habitat can sustainably support. Beyond this point, resources such as food and space simply cannot support further growth.
Q1.The flow of energy in an ecosystem is: Answer: (b) Unidirectional. Energy flows from the sun to producers and then to consumers, and unlike nutrients, it is never recycled back.
Q2.Which of these is a primary producer in most ecosystems? Answer: (b) Green plants. Through photosynthesis, they convert solar energy into chemical energy, forming the base of nearly every food chain.
Q3.Gross Primary Productivity, or GPP, of an ecosystem refers to: Answer: (b) Total rate of production of organic matter during photosynthesis. Once respiratory losses are subtracted from GPP, what remains is called net primary productivity.
Q4.Which pyramid is always upright and never inverted, in any ecosystem? Answer: (c) Pyramid of energy. Since energy is always lost as heat at each transfer, the amount available necessarily shrinks as it moves up trophic levels.
Q5.Decomposers play a key role in ecosystems mainly by: Answer: (b) Breaking down dead organic matter and releasing nutrients back into the soil. Without this recycling step, essential nutrients would stay locked up in dead material indefinitely.
Q1.The term biodiversity was popularised by: Answer: (b) Edward Wilson. He helped bring the concept into mainstream scientific and public conversation during the 1980s.
Q2.Species diversity is generally observed to be highest: Answer: (b) Near the equator, in tropical regions. This pattern, where diversity steadily falls as you move away from the equator, is often called the latitudinal gradient.
Q3.A species that exists only in a particular geographical area and nowhere else is called: Answer: (a) An endemic species. India's Western Ghats and the northeastern states are particularly rich in species found nowhere else on Earth.
Q4.The IUCN Red List primarily categorises species based on their: Answer: (b) Risk of extinction. Categories range from Least Concern all the way up to Extinct, giving a standard way to track how threatened a species really is.
Q5.In situ conservation refers to protecting species: Answer: (b) In their natural habitat, such as national parks and sanctuaries. This is generally considered the more effective long term conservation strategy compared to ex situ methods.
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| Chapter 03 Reproductive Health MCQs Set 01 |
| Chapter 03 Reproductive Health MCQs Set 02 |
| Chapter 03 Reproductive Health MCQs Set 03 |
| Chapter 12 Ecosystem MCQs Set 03 |
| Chapter 12 Ecosystem MCQs Set 04 |
| Chapter 12 Ecosystem MCQs Set 02 |
| Chapter 12 Ecosystem MCQs Set 01 |
Free study material for Biology
FAQs
For the 2026-27 session, MCQs and objective-type questions carry around 20% weightage. CBSE has introduced 30% competency based questions as MCQs and they are important part of the Class 12 Biology paper.
You can access the latest chapter-wise MCQs for Class 12 Biology for free from StudiesToday.com. All questions are based on the latest syllabus and current academic year.
Yes, our Biology practice bank includes the new pattern of Assertion Reasoning and Case Study based MCQs. They have been designed to test the analytical skills of Class 12 students.
Solving Class 12 Biology MCQs regularly improves speed and accuracy as these are objective questions can get you 100% marks if your understanding of the topic is clear.
Yes, all Class 12 Biology MCQs and answers are accessible on any device at your convenience.
No, all Biology Multiple Choice Questions (MCQs), practice papers, and solutions for Class 12 are available for free for students to get more marks school exams.