Question

what is the primary reason cells undergo cellular respiration?
to supply plants with carbon dioxide
to convert food to useable energy
to create energy from the sun
to get rid of wastes

Explanation:

Cellular respiration is a process by which cells break down food molecules (such as glucose) and convert them into a form of energy that the cell can use, namely ATP. It is not about supplying plants with carbon - dioxide (that's more related to photosynthesis's by - product), creating energy from the sun (which is photosynthesis), or primarily about getting rid of wastes.

Answer:

to convert food to useable energy