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.

Temperature is usually uniform throughout a cell (Ans. C)

Explanation:

Heat or thermal energy is a kinetic energy. That is connected with the random movements present in the atoms. Temperature is usually uniform throughout the cell so the most cell can not harness heat to perform work.

Heat is a type of energy which is transfer from one body to another body due to the temperature difference.

It can only perform work if it is transferred from one source which is warmer to a body which is cooler. The temperature in living organisms is usually kept very constant due to the process of homeostasis.