Final answer:
Facilitated diffusion is interpreted as a passive form of carrier transport that moves substances down their concentration gradient without using cellular energy, utilizing carrier proteins to facilitate the process.
Step-by-step explanation:
Facilitated diffusion is best interpreted as d. a passive form of carrier transport. Unlike active transport, facilitated diffusion does not require energy from the cell as it involves the movement of substances across the cell membrane from an area of higher concentration to an area of lower concentration. This movement is facilitated by carrier proteins or channels in the cell membrane, making the process more efficient than simple diffusion. The use of carrier proteins is the key distinction between simple passive diffusion and the facilitated type. Since facilitated diffusion moves substances along their concentration gradient (from high to low) without the use of cellular energy, it differs from active transport mechanisms like ion pumps and phagocytosis, which do require energy to move substances against their concentration gradient.