Is a source of genetic variation that involves the swapping of sections of chromosomes during meiosis. a. translation b. transcription c. fertilization d. crossing over

D.) Crossing over is a source of genetic variation that involves the swapping of sections of chromosomes during meiosis.

the areas around the equator

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.