Question

a) Both A and R are true, and R is correct explanation of the assertion.
b) Both A and R are true, but R is not the correct explanation of the assertion.
c) A is true, but R is false.
d) A is false, but R is true.

12. Assertion(A): The stomata generally open up during the night and remain closed
during the day.

Reason (R): They help in the exchange of carbon dioxide and oxygen.​

Answer 1

Required Answer :

Stomata is generally opened during the day to perform photosynthesis. They take in Carbon dioxide and releases oxygen as a result of exchange of gases.

But,

• In CAM plants or succulents, Stomata are open during the night to reduce the rate of transpiration during the day.

• It is to reduce water loss from the aerial parts of the plants because they generally grow in arid and extreme hot climate$.$

Still,

In majority, the plants in terrestrial and aquatic habitat, the stomata is open due to turgor pressure for gaseous exchange and transpiration. Hence, The correct option is:

• A is false, but R is true (D)

Because in the first statement of Assertion, Generally is mentioned which is turning the sentence entirely false.

Answer 2

Answer:

Answer :-

Option D

Explanation :-

Assertion is False

The assertion is wrong because in some plants the stomata is open during day. It is because they make photosynthesis and they help in transporting carbon dioxide.

Reason is true

They help in the exchange of carbon dioxide and oxygen.

Therefore :-

The assertion is False but reason is True.