In C3 plants the conservation of water promotes. a. photorespiration. b. a shift to C4.c. photosynthesis. d. the opening of stomata. e. the light reactions.

A) photorespiration.

Explanation:

Photorespiration is the harmful metabolic process which takes place when the concentration of oxygen in the leaf increases compared to carbon dioxide.

The RUBISCO enzyme which usually binds the carbon dioxide now binds the oxygen and form the phosphoglycolate and 3 phosphoglycerate. The phosphoglycolate is lost through the Calvin cycle as Carbon dioxide molecule. This loss proves harmful to the plants.

The photorespiration occurs when the plant faces high temperature therefore n order to prevent water loss the stomata gets closed. This result in the binding of the oxygen to the RUBISCO and thus photorespiration begins.

Thus, Option-A is correct.