Which of the following determines the sex of an offspring?

a. the male sperm

b. the thickness of the cell membrane

c. the female egg

d. none of the above

The answer is A because the males sperm determines the sex of a baby.The determines sperm is carrying an X or Y chromosome.

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.

igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.