When a cell needs energy, it brings in nutrients and break it down and supply energy to the cell

This question is incomplete, the complete question is: When a cell needs energy, I take in nutrients break them down, and supply energy to the cell. I can also convert stored energy in the cell to food. I am a?

The answer is MITOCHONDRION

Explanation:

All living organisms need energy at the cellular level to carry out their cellular activities. This energy is obtained by eating food. The energy in food is stored in the bonds of the sugar molecule that is contained in it.

However, via a process called CELLULAR RESPIRATION, the stored energy in food is broken down and used to synthesize a form of energy usable by the cell called ATP. This important process occurs in the organelle called MITOCHONDRION.