The imaginary line that circles earth halfway between the north and the south poles is the

The imaginary line that circles the globe halfway between the North and South Poles is called 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.