A single stickleback fish with pelvic armor was found in a p

A single stickleback fish with pelvic armor was found in a population of freshwater stickleback fish that lacks pelvic armor. The rare appearance of pelvic armor in this fish is best described as __________.

Solution

The answer is: a. an atavism.

A single stickleback fish with pelvic armor was found in a population of freshwater stickleback fish that lacks pelvic armor. The rare appearance of pelvic armor in this fish is best described as an atavism.

The sihngle stickleback fish with pelvic armor might have reverted back to its ancestral form.