Biology is the study of living things, and biochemistry is--well, we'll get to that. We were going to look at your epithelial cells, right?

[She doesn't wait for an answer, just turns to the bench and starts unwrapping the cotton swab.]

The microscopes over there [she nods at them] magnify whatever they're looking at, so you can see teeny, tiny things like cells. They're sort of like bricks that make up a house, except they make a life form.