Which of the following is an example of stabilizing selection?
a. Over time, Equus developed strength, intelligence, speed, and durable grinding teeth.
b. British land snails mainly have two different phenotypes.
c. Swiss starlings usually lay four or five eggs, thereby increasing their chances of more offspring.
d. Drug resistance increases with each generation; the resistant bacteria survive, and the nonresistant bacteria get killed off.
e. All of these are correct