By law when can a veterinary practice in California charge client for a written prescription?

it's anything that aren't producers and consumers.

explanation:

you've got to be clear on what "this" is

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.