Final answer:
Metabolism is not a mechanism that enables molecules to move across capillary endothelial cells; it is the set of life-sustaining chemical reactions in organisms. Mechanisms that enable such movement include diffusion, active transport, and osmosis.
Step-by-step explanation:
The mechanism that does not enable molecules to move across capillary endothelial cells is d. Metabolism. Metabolism refers to the chemical processes that occur within a living organism in order to maintain life. It includes the breakdown of substances to get energy and the use of energy to build up substances necessary for life. These processes do not directly result in the movement of molecules across cell membranes.
Mechanisms that do enable such movement include:
- a. Diffusion: The movement of molecules from an area of higher concentration to an area of lower concentration.
- b. Active Transport: The process of moving molecules against their concentration gradient, using energy usually in the form of ATP.
- c. Osmosis: A specific kind of diffusion focused on the movement of water molecules across a semi-permeable membrane.