Answer: Matter and energy cannot be created or destroyed, but can change from one form to another.
Explanation: According to first law of thermodynamics, energy of a closed system remains conserved and thus energy can neither be created nor be destroyed, it can only transform from one form to another.

= change in internal energy
q= heat absorbed or released
w= work done y or on the system
Thus change in energy is brought by work or heat which are also forms of energy. Thus energy gets transformed from on form to another.