Answer: The correct answer is A) Gather and respond to stimuli.
Stimulus is any detectable change in the internal or external environment of an organism that makes the organism respond towards it. Organisms give appropriate response to any stimulus ( that is accompanied by central nervous system) and it helps in maintaining the homeostatsis ( stable environment) of the body.
Example of stimulus- Hunger is an internal stimulus that causes an organism to take food, which is essential for survival.
Thus, Gather and response to stimuli is basic function of any organism to stay alive.
