The crystals that form in slowly cooling magma are

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.

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.