The spleen and the thymus work together to fight infection. These organs together make up which next level of organization?

answer; the correct answer is conflict- related aggression; +

1. a tropical dry forest carries out more rapid nutrient cycling

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.

the endomembrane system i think