Across
- 1. controls the quantity of light entering the eye
- 3. structure that closed the trachea when a bolus is swallowed
- 7. outer layer skin
- 8. collects and directs sound waves into the ear canal
- 9. alveoli damage
- 11. substance found in cigarette smoke
- 12. exchange of gas occur
- 13. response of plants towards water
Down
- 2. involuntary action
- 4. detects light and produces nerve impulse
- 5. respiratory system of insects
- 6. help to listen to the heartbeat
- 10. most prey have this vision