How big an image can be
How sharp an image can be
How many lenses a microscope uses
How much light is needed to see an image
Single celled organisms
Many celled organisms
To prevent oxygen from entering the cell
To prevent water from entering the cell
To perform different functions in each cell
To protect and support the cell
They convert energy from food molecules into energy the cell can use.
They store energy from food molecules.
They store energy from sunlight
They produce nucleic acids that release energy