<span>Active transport is the movement of molecules across a cell membrane from a region of their lower concentration to a region of their higher concentration—in the direction against some gradient or other obstructing factor (often a concentration gradient).</span>
<span>A biologist can infer from a population that is uniformly distributed through its habitat that it has reached it's carrying capacity. If resources were unevenly distributed through the environment, you would not see a uniform distribution of the population itself.</span>
