Final answer:
The statement that diffusion uses cellular energy is not true; it is a passive process that requires no energy, occurring in living and nonliving systems and allowing substances to move into and out of cells.
Step-by-step explanation:
The question being asked is which statement is not true about diffusion. Statement (a) 'Uses cellular energy' is not true regarding diffusion as it is a passive process. Diffusion does not use cellular energy. Instead, it involves the movement of molecules from an area of high concentration to an area of low concentration until the concentration is equalized across space. This passive process occurs in both living and nonliving systems and can transport substances into and out of cells. Diffusion is powered by the random kinetic energy of molecules, which causes them to spread out evenly in the available space, dissipating concentration gradients without the need for external energy.