Question

Assertion (A): The movement of water and dissolved salts in xylem is always upwards.

Reason (R): The upward movement of water is due to low pressure created by transpiration.

Options

• Both A and R are true and R is the correct explanation of A.

• Both A and R are true but R is not the correct explanation of A.

• A is true but R is false.

• A is false but R is true.

Answer 1

Both A and R are true and R is the correct explanation of A.

Explanation:

The assertion is true because water and mineral transport via the xylem is strictly unidirectional, moving exclusively upward from the roots to the leaves. The reason is also true and provides the correct explanation because this upward transit is driven by transpiration, which evaporates water from leaves to create a low-pressure suction zone. This suction acts like a drinking straw, generating a pulling force that continuously draws water columns upward through the xylem tubes.