Answer:
The answer to this question is option A. transpiration.
Step-by-step explanation:
The process of transpiration requires a plant structure called stomate. This structure controls the transpiration in the plant, and its release of gases too.
Thinking of a desert plant as an example, they're well adapted due to several years of adaptation to this environment, so they have some structures that help them conserve water, for example sharp spines, these spines help maintain body temperature, losing less water, such as big roots, that are in constant search for water underneath the ground. But the stomates are here too, when there's a lot of water available, they are open, but once there's no resource such as this, it keeps itself closed not to lose water.