Digestion is necessary because when food enters the body it has to be broken down in smaller particles and use for energy and growth for other parts of our body. If food does not digest it can cause acid reflux and other diagnoses.
It cannot be a bacteria because bacteria is made up of one cells, as it is a unicellular organism. Secondly, chlorophyll is the chemical that is in plants that makes the leaves on said plant green. So that makes the correct answer plants and proves why C.Bacteria is wrong.