Other than photosynthesis, _________________ is the main process of exchange at night.

Correct option is C

The correct answer is option (c) carbon dioxide

Information booster :

At night, since there is no sunlight, plants do not perform photosynthesis (which requires sunlight to produce oxygen and consume carbon dioxide). Instead, they continue respiration, which involves absorbing oxygen and releasing carbon dioxide.

• During respiration, oxygen is consumed, and carbon dioxide is released, similar to the way animals breathe.
• This is in contrast to the day, when photosynthesis takes place and plants take in carbon dioxide and release oxygen.

So, the main gas exchange at night is carbon dioxide.