Explain how genetic variation occurs in single-celled organisms that only reproduce asexually. For full credit you should distinguish between vertical and horizontal gene transfer and include specific examples and/or mechanisms of how an organism's genetic code might change.

so whats the answer

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.

c. heat from the poles back down towards the equator.