What happened to the matter and the energy of a watermelon when it decomposes?

Answer: Decomposition is a process in which complex organic molecules are converted into simple inorganic forms, which can be easily degraded.

Explanation:

The watermelon is a food source for decomposers. The soft fleshy part get decomposed and degraded easily but the hard thicker rind takes long. The soil decomposers like bacteria, earthworms and fungi will convert the organic matter in the watermelon into inorganic components. This way the matter is converted into a form which can be utilized by the decomposers as a source of energy and some components also improves the quality of soil.