Which process allows cells to absorb larger molecules or tiny organisms that cannot pass through the plasma membrane?

The correct choice identifies endocytosis as the process that enables cells to engulf larger molecules or small organisms that are too large to pass through the plasma membrane directly. Endocytosis involves the cell membrane folding inward to form a pocket around the substance. This pocket then pinches off to create a vesicle that brings the engulfed material into the cell.

Endocytosis is particularly important for the uptake of nutrients, signaling molecules, and even pathogens, allowing the cell to incorporate materials that are essential for its functions and survival. This mechanism is crucial for processes such as phagocytosis, where cells, like white blood cells, actively reach out and engulf bacteria and other pathogens.

Other processes such as exocytosis, diffusion, and osmosis do not serve the same purpose. Exocytosis is the process by which cells expel materials, diffusion is the movement of molecules from an area of high concentration to an area of low concentration without the need for energy, and osmosis is specifically the diffusion of water across a selectively permeable membrane. None of these processes involve the absorption of larger molecules or tiny organisms in the same manner as endocytosis.