Select the correct answer. Which condition is a cause of impotency in men?
A.
undescended testicles that persist beyond puberty
B.
the inability of the penis to become erect
C.
a vasectomy, which is a surgical procedure to cut the vas deferens
D.
a low production of sperm in the testes
E.
the absence of the vas deferens in a male from birth

The image shows the evolution of a species of fish. a few fish from a population developed different social behaviors and evolved into different species. two fish according to the image, the fish underwent . the new species of fish had mating seasons that were different from that of the original fish. because of the differences in mating seasons, the fish underwent reproductive isolation. this mode of isolation would be .