Personally, I'd say that the answer is adaptation, but the closest thing there is, is evolution.
C. they are the same species and have different traits
The answer is C.) The volume of fluid in Image B is greater than that of Image A.
The appropriate answer is the peristaltic muscle muscle contractions.
Peristalsis, involves involuntary movements of the longitudinal and circular muscles, primarily in the digestive tract but may take place in other hollow tubes of the body, that occur in progressive wavelike contractions. Peristaltic waves occur in the esophagus, stomach, and intestines.
C is the answer to this question...