Most cells cannot harness heat to perform work because
a. Heat does not involve a transfer of energy.
b. Cells do not have much thermal energy; they are relatively cool.
c. Temperature is usually uniform throughout a cell.
d. Heat can never be used to do work.

Thermodynamics involves the study of energy transfer, and in biological systems, it explains how cells convert energy from one form to another. Cells primarily use chemical energy, such as ATP, rather than heat, because heat energy is not efficiently harnessed for cellular work due to uniform temperature distribution within cells.

Cells maintain a relatively uniform temperature, which means there is little temperature gradient to drive processes that rely on heat energy. This uniformity prevents the effective use of heat for work, as work typically requires a difference in energy levels or temperature to be performed efficiently.

Cells rely on mechanisms like ATP hydrolysis for energy transfer, which involves chemical reactions rather than heat. These processes are more controlled and efficient for cellular functions, as they provide a direct and manageable way to harness energy for metabolic activities, unlike the diffuse nature of heat energy.