Answer: maintain homeostasis
Step-by-step explanation:
Homeostasis is the feature of the body resists any change occurring in it with respect to the changes happening in the external environment.
The trees shed their leaves in autumn so as to conserve water in autumn season. As in autumn season the trees may experience the scarcity of water due to lack of rainfall or low rainfall in a region. As the leaves may loose water by the process of transpiration also they will utilize water for the process of photosynthesis. The trees may experience wilting or may die. This is a process of maintenance of homeostasis in terms of conservation of water.