There are 7 modes of nutrition in protozoa: 1) holozoic/zoo-trophic, 2) pinocytosis, 3) autotrophic/holophytic, 4) saprozoic, 5) parasitic, 6) coprozoic, and 7) mixotrophic. Digestion occurs intracellularly within food vacuoles, where the vacuole contents undergo changes in pH and size. Absorption and assimilation occurs as digested food diffuses from vacuoles and is used to manufacture protoplasm, with excess stored as glycogen. Undigested remains are egested from the body surface or through a cytoproct opening.