Vacuole. Amoeba is a unicellular organism formerly grouped under Kingdom Protista. Amoeba in freshwater need contractile vacuole to control input and output of water. (osmosis). Without this structure, ameboid cells will be filled with water and eventually burst.
A cell can only respond to signals from other cells, not from the physical environment. receptor activation. The ability of a specific tissue or organ to respond to the presence of a hormone is dependent on: the presence of the appropriate receptors on the cells of the target tissue or organ.
The answer is Chronic<span> Stress</span>
