E. Both a) and d) are correct. ??? ??? ??? Which of the following is NOT a form of kinetic energy? a covalent bond linking phosphate molecules ??? ??? ??? Every time a source of energy is converted from one form to another: some of the energy is converted to heat, which is one of the least usable forms of kinetic energy. ??? ??? ??? Within the study of thermodynamics, a closed system is defined as