Question

Assertion: Stomata remain open during day.

Answer 1

 stomata openby day and close at night.During the day, photosynthesis requires that the leaf mesophyll be exposed to the air to get CO2. At night, the stomataclose to avoid losing water when photosynthesis is not occurring

Answer 2

Answer:

Stomata remains open during the day time due to availablity of sunlight. When sunlight is available photosynthesis takes place and the gaseous exchange is required at a higher rate.

So more gaseous exchange due to high rate of Photosynthesis leads to opening of stomata in the day.

Assertion and reason both are correct and the reason is the correct explaination for the assertion.