Gradualism is a pattern of evolution in which. a. a single species evolves into several closely related species. b. several distantly related species develop similarities. c. a species evolves at a slow, steady pace. d. a species has periods of little evolution interrupted by periods of rapid evolution.

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; both surfaces of the membrane are nonpermeable