Across
- 2. Oxygen enters the blood through these.
- 6. Living things need oxygen to do this.
- 7. Water enters a fish through this.
- 8. Oxygen enters this during gaseous exchange.
- 10. These make food using carbon dioxide.
Down
- 1. These obtain oxygen from water.
- 3. Tiny openings are found mostly on these.
- 4. Moves from the lungs into the blood.
- 5. This gas leaves the blood in the lungs.
- 9. Fish obtain oxygen dissolved in this.