NCERT Class 10 Science — Chapter 3: How do Organisms Reproduce?

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Assertion (A): Self-pollination guarantees the introduction of genetic variation in the offspring. Reason (R): Cross-pollination involves the transfer of pollen from the anther of one flower to the stigma of another flower.

Official previous-year question

Verified 1 Aug 2026.

Options

ABoth A and R are true and R is the correct explanation of A
BBoth A and R are true but R is NOT the correct explanation of A
CA is true but R is false
DA is false but R is true

Did you get this right?

Solution

Correct Option

The correct option is

A is false but R is true

Explanation

Pollination is the process of transferring pollen grains from the male anther to the female stigma of a flower. It is broadly categorized into self-pollination (autogamy and geitonogamy) and cross-pollination (xenogamy) based on the genetic source of the pollen.

Statement-wise Analysis

Assertion (A): Incorrect. Self-pollination involves the transfer of pollen within the same flower or between flowers of the same plant. Since the genetic material originates from a single parent, the offspring are genetically identical or very similar to the parent. Consequently, self-pollination promotes homozygosity and does not guarantee the introduction of genetic variation; rather, it maintains pure lines.
Reason (R): Correct. Cross-pollination is defined as the transfer of pollen grains from the anther of one flower to the stigma of another flower (usually on a different plant of the same species). This mechanism facilitates the mixing of genetic material from two different parents, thereby introducing genetic diversity.

Since the Assertion is false regarding the source of variation, and the Reason correctly defines the mechanism of cross-pollination,

A is false but R is true

is the correct answer.

Key Takeaway: Self-pollination reduces genetic variability and leads to inbreeding depression, whereas cross-pollination introduces genetic variation and evolutionary adaptability.

Your note

More from Chapter 3: How do Organisms Reproduce?

With reference to vegetative propagation in plants, consider the following statements: 1. It can result in earlier flowering and fruiting than seed propagation. 2. It enables multiplication of plants that no longer produce seeds. 3. It helps maintain parental traits due to genetic similarity. 4. It is not used for grapes. Which of the statements given above are correct?

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Consider the following statements about the male reproductive tract: 1. The vas deferens enters the kidney directly. 2. The urethra serves as a common passage for sperm and urine. 3. Secretions from accessory glands make transport easier and provide nutrition. Which of the statements given above are correct?

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In human reproduction, fertilisation normally occurs at, and implantation occurs at, respectively:

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How many of the following are listed as bacterial sexually transmitted infections: gonorrhoea, syphilis, warts, HIV-AIDS?

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In which of the following organisms does the body break into fragments upon maturation, with each fragment growing into a new individual?

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Keep practising Chapter 3: How do Organisms Reproduce?

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Correct Option

The correct option is

A is false but R is true

Explanation

Statement-wise Analysis

Assertion (A): Incorrect. Self-pollination involves the transfer of pollen within the same flower or between flowers of the same plant. Since the genetic material originates from a single parent, the offspring are genetically identical or very similar to the parent. Consequently, self-pollination promotes homozygosity and does not guarantee the introduction of genetic variation; rather, it maintains pure lines.
Reason (R): Correct. Cross-pollination is defined as the transfer of pollen grains from the anther of one flower to the stigma of another flower (usually on a different plant of the same species). This mechanism facilitates the mixing of genetic material from two different parents, thereby introducing genetic diversity.

Since the Assertion is false regarding the source of variation, and the Reason correctly defines the mechanism of cross-pollination,

A is false but R is true

is the correct answer.

Key Takeaway: Self-pollination reduces genetic variability and leads to inbreeding depression, whereas cross-pollination introduces genetic variation and evolutionary adaptability.