Which of the following is an example of homeostasis? a cactus stores water during wet periods, allowing it to live through dry periods. a human participates in vigorous activity on a hot day and eventually suffers from dehydration. a snake rests in the sun on a summer day, and its body temperature eventually becomes too hot for survival. a human body loses too much heat on a cold day, and hypothermia occurs.

Among the given choices, an example of homeostasis is the first choice, which is when a cactus stores water during wet periods, allowing it to live through dry periods

Homeostasis refers to the ability or tendency of a system (i.e. physiological) to maintain a stable internal environment even when environmental or external conditions may change or vary.

The other examples given in the choices do not reflect equilibrium because they depict the inability of the body or organisms to maintain a stable internal environment because of failure to cope with changes in the external environment (too much heat, cold, and water loss). 

The answer is option a