Answer the following question given this paragraph: 

All forms of energy can be interconverted. Three things can change the energy of an object: the transfer of heat, work performed on or by an object, or some combination of heat and work.


Q: All forms of energy can be interconverted. three things can change the energy of an object: the transfer of heat, work performed on or by an object, or some combination of what?


A:
heat and work