The measure of chemical energy in cells and in food the energy available from high energy bonds in organic molecules

the correct answer is c   with the systems

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.

its temperature is increasing. this causes molecular vibrations to increase.