Across
- 3. Oxygen-bound haemoglobin compound
- 8. Harmful disease-causing microbes
- 11. Oxygen-transporting blood cells
- 13. Waste gas expelled during exhalation
- 16. Rib muscles involved in breathing
- 17. Muscle action during inhalation
- 18. Pathogen-fighting proteins
- 19. Liquid portion of blood
- 20. Iron-containing red blood protein
Down
- 1. Dome-shaped breathing muscle
- 2. Cellular energy-producing organelles
- 4. Lung air sacs
- 5. Infection-fighting blood cells
- 6. Tiny blood vessels
- 7. Cellular energy-release process
- 9. Simple sugar used for cellular energy
- 10. NOT present in the red blood cells
- 12. Process inhaling and exhaling
- 14. Muscle action during exhalation
- 15. Essential gas for aerobic respiration