The right option is; Absorption
Transport of a substance from the lumen (cavity) of an organ into one side of a cell and out the other side of the cell into the ecf is called absorption.
Absorption is the process of assimilating substances into cells or through the tissues and organs. Absorption is done through osmosis or diffusion. Absorption of substances takes place within the body such as the absorption of drugs into the bloodstream, and the absorption of nutrients by the digestive system.