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).