Across
- 4. a group of atoms joined together in a particular way like h2O
- 6. the molecules we are made up of
- 8. takes in oxygen releases carbon dioxide
Down
- 1. transports molecules to and from all cells of the body
- 2. the body system that breaks down food
- 3. a molecule that organisms can use to release energy
- 4. the way we digest food
- 5. made by glucose and oxygen
- 6. how we make energy
- 7. a set of interacting parts forming a complex whole