Across
- 2. An organ where gas exchange occurs between air and blood
- 6. A group of organs that work together to perform a function
- 7. A gas needed by cells to release energy
- 8. a tube that carries blood away from the heart
- 9. A body part that performs a specific function
Down
- 1. A tiny air sac in a lung where gas exchange occurs
- 3. An opening in the nose where incoming air is warmed and filtered
- 4. A thin layer that forms a barrier
- 5. A tube that carries air through a lung
- 6. The process used by animals to exchange gases with the atmosphere