Where do you think the matter and energy that were in a watermelon goes after it's molded and unable to be eaten?

The matter and energy is circulated back into nature regardless whether it is eaten or molded.

Explanation:

A molded watermelon is infected with molds (microorganisms of fungal origin).

The energy within the wateemelon is used up by the molds to fuel its life processes. Most of the matter is converted to energy in this form. All in all, the energy and matter goes into nature.