When the cell concentrates potassium within, against the natural tendency of matter, it is performing a. passive diffusion b. facilitated diffusion c. active transport d. pinocytosis

What is a food chain? a. different animals located in different communities b. energy transferred from the sun to plants and then to a series of living things c. rows of crops, such as lettuce, in a field d. animals using one another as food for energy and growth