They are all pure elements. They are all made of cells. They are all living creatures. They are all made of atoms.
I gave my students this multiple choice question: What do water, aluminum, redwood trees, and valley quail all have in common?

Only one answer is correct among these 4 choices:
- They are all pure elements.
- They are all made of cells.
- They are all living creatures.
- They are all made of atoms.

Could you tell me which one is correct?

They are all made of atoms.