What is the relationship between passive and active transport?

use ATP to pump the nutrient against/up the concentration gradient. Transport occurs from a low concentration of solute to high concentration of solute. Requires cellular energy. And Passive transport is Movement of molecules DOWN the concentration gradient. It goes from high to low concentration in order to maintain equilibrium in the cells. Does not require cellular energy.
Active and passive transport are biological processes that move oxygen water and nutrients into cells and remove waste products. Active transport requires chemical energy because it is the movement of biochemicals from areas of lower concentration to areas of higher concentration. On the other hand passive trasport moves biochemicals from areas of high concentration to areas of low concentration; so it does not require energy.
Example of active transport is phagocytosis pinocytosis sodium/potassium pump secretion of a substance into the bloodstream (process is opposite of phagocytosis & pinocytosis)
And that of passive transport is and facilitated diffusion.