Across
- 2. Main tubes splitting from the trachea into the lungs.
- 3. Tiny air sacs, where gas exchange occurs.
- 5. Primary respiratory organs in mammals, birds, and reptiles.
- 7. DIOXIDE Waste gas exhaled by animals.
- 9. System of tubes used by insects for respiration.
- 10. External openings in insects for breathing.
- 12. Protein in red blood cells that transports oxygen.
Down
- 1. Large muscle controlling breathing in mammals.
- 4. Scientific name for the windpipe, leading to the lungs.
- 6. Respiratory organs found in fish and some amphibians.
- 8. Gas is needed by animals to produce energy.
- 11. The overall process of bringing in oxygen and releasing waste.