Final answer:
Phagocytosis, pinocytosis, and receptor-mediated endocytosis all involve the formation of vesicles to uptake substances into the cell.
Step-by-step explanation:
All three processes, phagocytosis, pinocytosis, and receptor-mediated endocytosis, involve the cellular uptake of substances through the formation of vesicles. This is the common feature in each of these processes. In phagocytosis, the cell membrane engulfs a large particle and forms an intracellular vacuole. In pinocytosis, the cell membrane surrounds a small volume of fluid and forms a vesicle. In receptor-mediated endocytosis, specific substances bind to receptors on the cell membrane, which then invaginates and forms a coated vesicle.