Can a single cell also be an organism?why?

Hey me with this one❤❤❤❤ every organism needs food. does a cell also need it? explain very briefly.

What is the main function of the central vacuole in a plant cell? a. absorbs energy from the sun to produce food b. holds water and maintains turgor pressure c. breaks down molecules to release energy d. contains the cell's genetic material

Construct at least two possible hypotheses for the student’s experiment.