When dry environmental conditions exist, guard cells close the openings in leaves to reduce the loss of water from the plant. this process is an example of a feedback mechanism that plants use in order to
a. maintain homeostasis.
b. expend their resources.
c. absorb more solar energy.
d. produce more chlorophyll.

Ans.

Homeostasis is defined as a process that keeps the organism's internal environment as constant as possible. Water works as a thermoregulator, solvent, and play role in almost all metabolic reactions.

Guard cells maintain homeostasis in plants as these cells prevent water loss from plants during hot and dry conditions by closing their opening. On the other hand, opening of guard cells during dry conditions will cause loss of water by transpiration and plant will not maintain the homeostasis.  

Thus, the correct answer is option A). 'maintain homeostasis.'

cells spend most of their time in interphase