Biology Chapter-Wise Revision Test – MCQs

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CBSE Class 10 Biology Chapter-Wise Revision Test – MCQs

Practise 30 biology multiple-choice questions with instant answer checking and clear explanations to strengthen your understanding of important Class 10 Science concepts.

Class 10 CBSE30 MCQs5 Topic Areas2026–27 Preparation

About This Biology Revision Test

This NCERT-oriented practice test reviews nutrition, respiration, transportation, excretion, nervous coordination, hormones, reproduction, heredity and environmental sustainability. Select one answer for each question and open its explanation to revise the concept.

Topic 1 · Q1–Q8Life Processes

Topic 2 · Q9–Q14Control and Coordination

Topic 3 · Q15–Q20How Do Organisms Reproduce?

Topic 4 · Q21–Q26Heredity

Topic 5 · Q27–Q30Our Environment

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Topic 1: Life Processes

1

Which mode of nutrition is followed by green plants that prepare their own food?

View answer and detailed explanation

Correct answer: B. Autotrophic nutrition. Green plants make their own food through photosynthesis. Chlorophyll absorbs light energy, which is used to convert carbon dioxide and water into carbohydrates. Oxygen is released during this process. Autotrophs produce organic food from inorganic raw materials, whereas heterotrophs depend on other organisms for food.

Overall equation:
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
Light and chlorophyll are required; the equation summarises the overall process.

2

Which enzyme in saliva begins the digestion of starch in humans?

View answer and detailed explanation

Correct answer: C. Salivary amylase. Salivary glands release saliva containing salivary amylase, which begins breaking down starch into smaller carbohydrate molecules. Chewing also increases the surface area of food and mixes it with saliva. Protein digestion begins mainly in the stomach with pepsin, while bile helps emulsify fats in the small intestine but is not an enzyme.

3

Where does the exchange of oxygen and carbon dioxide take place in human lungs?

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Correct answer: A. Alveoli. Alveoli are tiny air sacs surrounded by a dense network of blood capillaries. Their large surface area, thin walls and rich blood supply make gas exchange efficient. Oxygen diffuses from the air in the alveoli into the blood, while carbon dioxide diffuses from the blood into the alveoli and is breathed out.

4

Which blood component transports oxygen from the lungs to body tissues?

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Correct answer: D. Red blood cells. Red blood cells contain haemoglobin, a pigment that binds oxygen reversibly. This enables oxygen to be transported from the lungs to tissues where it is needed for cellular respiration. Plasma transports dissolved substances, white blood cells help defend the body against infection, and platelets assist in blood clotting.

5

Which blood vessel carries oxygenated blood from the lungs to the heart?

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Correct answer: B. Pulmonary vein. Pulmonary veins carry oxygen-rich blood from the lungs to the left atrium of the heart. The pulmonary artery carries oxygen-poor blood from the right ventricle to the lungs. These vessels are named according to the direction in which they carry blood relative to the heart, not simply by their oxygen content.

6

Which tissue transports water and dissolved minerals from roots to the upper parts of a plant?

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Correct answer: C. Xylem. Xylem transports water and dissolved mineral salts from roots towards stems and leaves. Transpiration, the loss of water vapour from aerial plant parts, creates a pull that helps move water upward. Phloem transports sugars and other organic substances from sources, such as leaves, to areas where they are used or stored.

7

Which organ removes nitrogenous wastes from human blood to form urine?

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Correct answer: A. Kidneys. The kidneys filter blood and regulate water and salt balance. Their functional units, called nephrons, carry out filtration, selective reabsorption and secretion to produce urine. Urea is a major nitrogenous waste in human urine. The ureters carry urine to the urinary bladder, and the urethra carries it out of the body.

8

What is the main purpose of cellular respiration?

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Correct answer: D. Cellular respiration releases energy from food molecules such as glucose. In aerobic respiration, glucose is broken down using oxygen, producing carbon dioxide, water and energy that cells capture in ATP and other energy-transfer processes. Respiration is different from breathing: breathing exchanges gases, while cellular respiration consists of chemical reactions within cells.

Topic 2: Control and Coordination

9

Which part of a neuron receives signals from other neurons or receptors?

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Correct answer: B. Dendrites. Dendrites receive incoming signals and carry them towards the cell body. A neuron typically conducts an electrical impulse from the cell body along its axon towards the axon terminals. At a synapse, chemical messengers commonly transfer the signal to another neuron or target cell.

10

Which part of the brain is mainly responsible for posture, balance and coordination of muscular activity?

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Correct answer: C. Cerebellum. The cerebellum helps maintain balance, posture and coordination of voluntary muscular movements. The cerebrum is involved in conscious thought, memory and voluntary actions. The medulla regulates important involuntary activities, including breathing and heartbeat.

11

Which plant hormone promotes cell elongation and is involved in the bending of shoots towards light?

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Correct answer: A. Auxin. Auxin is a plant growth hormone involved in cell elongation. When light comes from one side, auxin distribution in a shoot changes, causing greater elongation on the shaded side. The shoot bends towards the light, a response known as positive phototropism. Insulin, thyroxine and adrenaline are animal hormones.

12

Which hormone helps regulate blood glucose levels by promoting the uptake and storage of glucose?

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Correct answer: D. Insulin. Insulin is secreted by beta cells in the pancreas. It helps lower blood glucose by promoting glucose uptake in responsive tissues and encouraging storage, including as glycogen. Insufficient insulin production or impaired insulin action can cause diabetes mellitus. Glucagon is another pancreatic hormone that generally raises blood glucose when it becomes too low.

13

What is a reflex action?

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Correct answer: B. A reflex action is a rapid, automatic response to a stimulus, such as withdrawing a hand from a hot object. A reflex arc commonly involves a receptor, sensory neuron, spinal cord relay, motor neuron and effector. The spinal cord can coordinate many protective reflexes without waiting for conscious processing, although the brain receives information about the event.

14

Which gland secretes thyroxine, a hormone important for regulating metabolism?

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Correct answer: C. Thyroid gland. The thyroid gland produces thyroxine, which helps regulate the body's metabolic activities. Iodine is needed to synthesise thyroxine, so insufficient dietary iodine may contribute to goitre and other thyroid problems. Hormones travel through the blood and act on target cells with appropriate receptors.

Topic 3: How Do Organisms Reproduce?

15

Which type of reproduction involves only one parent and usually produces genetically similar offspring?

View answer and detailed explanation

Correct answer: A. Asexual reproduction. Asexual reproduction usually involves a single parent and no fusion of gametes. Offspring produced by mitotic division are generally genetically very similar to the parent, although mutations can introduce variation. Binary fission in Amoeba and budding in Hydra are examples of asexual reproduction.

16

Which method of asexual reproduction is commonly seen in Hydra?

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Correct answer: D. Budding. In Hydra, repeated cell division produces a small outgrowth called a bud on the parent's body. The bud grows and develops structures before detaching to live independently. This process is asexual because it does not involve the fusion of male and female gametes.

17

Where does fertilisation normally occur in the human female reproductive system?

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Correct answer: B. Fallopian tube (oviduct). In humans, fertilisation normally takes place in the oviduct, where a sperm cell may fuse with an ovum to form a zygote. The zygote undergoes cell division as it moves towards the uterus. Implantation normally occurs in the uterine lining, where the developing embryo can receive support.

18

What is the main function of the placenta during pregnancy?

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Correct answer: C. The placenta is a specialised interface between the developing fetus and the mother. It enables the transfer of oxygen and nutrients to the fetus and the movement of carbon dioxide and metabolic wastes away from it. Maternal and fetal blood normally remain separated by a tissue barrier, although substances can cross this barrier.

19

Which contraceptive method also helps reduce the risk of transmission of many sexually transmitted infections?

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Correct answer: A. Condoms. Condoms act as barrier contraceptives and reduce the risk of pregnancy and transmission of many sexually transmitted infections when used correctly and consistently. No contraceptive method is perfect, and condoms reduce rather than eliminate infection risk. Hormonal contraceptives and intrauterine devices help prevent pregnancy but do not provide equivalent protection against sexually transmitted infections.

20

What is the role of pollen grains in flowering plants?

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Correct answer: D. Pollen grains are produced in the anthers and carry the male gametophyte, which delivers male reproductive cells to the female reproductive structures. During pollination, pollen reaches a compatible stigma. A pollen tube grows towards the ovule, allowing a male gamete to participate in fertilisation. After fertilisation, the ovule develops into a seed and the ovary generally develops into a fruit.

Topic 4: Heredity

21

What is heredity?

View answer and detailed explanation

Correct answer: B. Heredity is the transmission of biological characteristics from parents to offspring through genetic information. Genes are segments of DNA that contribute to inherited traits. Offspring resemble their parents because they inherit genetic material from them, but they are not necessarily identical because genetic recombination and other processes create variation.

22

Where are genes located in most human body cells?

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Correct answer: C. Genes are DNA sequences that carry hereditary information. In human cells, most DNA is organised into chromosomes in the nucleus. Human body cells usually contain 46 chromosomes arranged in 23 pairs. Mitochondria also contain a small amount of DNA. DNA provides instructions for producing functional RNA and, for protein-coding genes, proteins that contribute to cell structure and function.

23

In a simple Mendelian cross, T represents tallness and t represents dwarfness in pea plants. If T is dominant, what is the phenotype of Tt?

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Correct answer: A. Tall. The genotype Tt is heterozygous because it contains two different alleles. Since T is dominant over t in this simplified example, one copy of T is sufficient for the tall phenotype. The recessive dwarf phenotype appears only when the genotype is tt. A dominant allele is not necessarily more common or biologically superior.

24

If two heterozygous tall pea plants (Tt × Tt) are crossed, what is the expected phenotypic ratio of tall to dwarf offspring under complete dominance?

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Correct answer: D. 3:1. Each parent can produce T or t gametes. The possible offspring genotypes are TT, Tt, Tt and tt. Three of these genotypes are tall and one is dwarf, producing an expected phenotypic ratio of 3:1.

Genotypic ratio: 1 TT : 2 Tt : 1 tt.
Phenotypic ratio: 3 tall : 1 dwarf.
These are expected probabilities for a sufficiently large number of offspring, not a guarantee for every small family or cross.

25

In humans, which combination of sex chromosomes is typically associated with a female?

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Correct answer: B. XX. In the standard human chromosomal pattern, females typically have XX sex chromosomes and males typically have XY. An egg usually contributes an X chromosome, while sperm may contribute X or Y. The sperm's chromosome therefore usually determines whether the resulting embryo has an XX or XY chromosome combination. Biological sex development is more complex than chromosomes alone, and variations also occur.

26

Why are variations important for the survival of a species?

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Correct answer: C. Variations produce differences among individuals. If the environment changes, some inherited variations may improve survival or reproductive success. Natural selection can increase the frequency of advantageous inherited traits over generations. Variation does not guarantee survival for every individual, but it provides the raw material on which natural selection acts.

Topic 5: Our Environment

27

Which organisms are called producers in an ecosystem?

View answer and detailed explanation

Correct answer: A. Producers, such as green plants and algae, convert light energy into chemical energy stored in organic molecules through photosynthesis. They form the base of many food chains by supplying food energy to consumers. In some ecosystems, such as certain deep-sea environments, producers can use chemical energy instead of sunlight.

28

Consider the food chain: Grass → Grasshopper → Frog → Snake. Which organism is the secondary consumer?

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Correct answer: D. Frog. Grass is the producer. The grasshopper feeds on grass and is the primary consumer. The frog feeds on the grasshopper and is the secondary consumer. The snake feeds on the frog and is the tertiary consumer in this simplified chain. An organism's trophic level depends on its feeding position within the particular food chain.

29

According to the approximate 10% law of energy transfer, how much energy is passed to the next trophic level if a level contains 10,000 J of energy?

View answer and detailed explanation

Correct answer: B. 1,000 J. Under the approximate 10% law commonly taught at this level, only about one-tenth of the energy available at one trophic level is transferred to the next. The calculation is:

Energy transferred = 10% × 10,000 J = 1,000 J.

Much of the energy is used for life processes or dissipated as heat, and not all biomass is eaten or assimilated. The 10% figure is a useful approximation, not an exact universal constant.

30

Why is the ozone layer important for life on Earth?

View answer and detailed explanation

Correct answer: C. The ozone layer in the stratosphere absorbs much of the Sun's harmful ultraviolet radiation, particularly UV-B and UV-C. Excessive ultraviolet exposure can damage DNA and harm living organisms. Certain ozone-depleting substances, including many chlorofluorocarbons (CFCs), release reactive chlorine or bromine species in the stratosphere that destroy ozone molecules.

Final Biology Revision Checklist

Photosynthesis, digestion, respiration, circulation and excretion.
Neurons, reflex actions, brain functions and plant and animal hormones.
Asexual and sexual reproduction, fertilisation and contraception.
Genes, dominant and recessive traits, Mendelian crosses and variation.
Food chains, trophic levels, energy transfer and ozone-layer protection.

Study tip: practise diagrams of the human digestive system, heart, nephron, neuron and reproductive systems where required by your syllabus. Revise definitions and practise explaining biological processes in your own words. Check the official CBSE 2026–27 syllabus for the final list of examinable topics.