The alveoli. These little air sacs are found on the end of the bronchioles and are the place where oxygen enters the blood and the carbon dioxide leaves.
A microscope is to see smaller things that you can’t see and it is a really good tool.
Here are the 3 parts of the cell theory:
1. Cells are the basic building blocks of any living things.
2. Any living thing is composed of more than 2 cells.
3. New cella arise from the old
I would guess C, hope that helps!
