The human female reproductive system is designed to
I. produce gametes in the ovaries.
II. support the development of a fetus in the uterus.
III. provide essential materials through the placenta.
IV. provide nutrition, or milk, from the mammary glands.

A. I and II only
B. I, II, III, and IV
C. II, III, and IV only
D. II and IV only

Answer is B

To answer this question, researchers studied populations of the dusky salamander (desmognathus ochrophaeus) living on different mountain ranges in the southern appalachian mountains. the researchers tested the reproductive isolation of pairs of salamander populations by leaving one male and one female together and later checking the females for the presence of sperm. four mating combinations were tested for each pair of populations (a and b)—two within the same population (female a with male a and female b with male b) and two between populations (female a with male b and female b with male a). the proportion of successful matings for each mating combination was measured. for example, when all the matings of a particular combination were successful, the researchers gave it a value of 1; when none of the matings were successful, they gave it a value of 0. then the researchers calculated an index of reproductive isolation that ranged from 0 (no isolation) to 2 (full isolation). the reproductive isolation value for two populations is the sum of the proportion of successful matings of each type within populations (aa + bb) minus the sum of the proportion of successful matings of each type between populations (ab + ba). the table provides data for the geographic distances and reproductive isolation values for 27 pairs of dusky salamander populations.

What would most likely happen if a person increased the amount of saturated fat in his or her diet? the person's risk of cardiovascular disease would increase. the person's risk of cardiovascular disease would decrease. the person's bad cholesterol would decrease. the person’s good cholesterol would increase.

Why are lipids and proteins free to move laterally in membranes?