Second Review of Classification: Simple Animal Phyla

11. Which of the following is not an adaptation to different environments that might keep two populations from meeting and intermixing their DNA, allowing them to develop towards separate species?

A) One requires habitats with at least 60 inches annual rainfall, the other needs about 20 inches annual rainfall.

B) One population requires air temps at 37 F, the other needs 75 F.

C) They live at widely different altitudes.

D) Their offspring are sterile.