Chapter 38

1. How long can an animal live without eating? 2. How long can an animal live without breathing? 3. Why is your body like a sponge? 4. What are cells? 5. How do they get their food? 6. How many kinds of waste come from the body cells? 7. How is each kind carried away from the body? 8. What does the blood carry from the lungs to the body cells? 9. Why does it not carry air? 10. What process keeps your body warm? 11. What happens if the body cannot get oxygen? 12. How are the human lungs formed? 13. What is the windpipe? What are the bronchi? 14. Draw a picture of the lung-tree showing how the tubes branch. 15. What is at the end of each tiny branch? 16. How do the windpipe and the esophagus differ in form? 17. Why is the windpipe stiff? 18. In what four ways is the air you breathe out different from that which you took in? 19. Why does lime-water become milky when you breathe into it? 20. When you run, why do you breathe more quickly? Why does your heart beat faster? 21. How can you improve your "wind"? 22. In fever, why do you breathe more rapidly? 23. How do the ribs and muscles help in breathing?