AP BIOLOGY

Detailed explanation-1: -It can also react in different ways after being exposed to something unpleasant; it may bend away, repel a noxious stimulus with its cilia, or swim in another direction. If it’s exposed to the stimulus repeatedly, it may start by bending, then try the other strategies.

Detailed explanation-2: -Amoebae and certain other single-celled organisms can sense and move through their environments without an elaborate nervous system, using a process called chemotaxis.

Detailed explanation-3: -The single cell of a unicellular organism such as an Amoeba performs all vital life activities (e.g., respiration, metabolism, repair, assimilation) and organismic level activities (e.g., intake of food, exchange of respiratory gases, excretion, reproduction).

Detailed explanation-4: -Unicellular organisms are made up of only one cell that carries out all of the functions needed by the organism, while multicellular organisms use many different cells to function. Unicellular organisms include bacteria, protists, and yeast.