The movement of molecules from high concentration to low concentration is called

Diffusion

Explanation:

Diffusion is a process of passive transport in which molecules move from an area of higher concentration to one of lower concentration.

answer: accepted answer: aquatic animals use the oxygen dissolved in water to carry out respiration. since the amount of dissolved oxygen in water is low as compared to the amount of oxygen in the air, therefore the rate of breathing in aquatic animals is much faster than it is in terrestrial animals.

explanation:

answer; the tunica intima also called tunica interna, consists of elastic fibers,connective tissue and smooth muscle cells;