296 BIOLOGY AND HUMx\N LIFE 



8. How does the digestive system of the frog resemble that of man ? 

 How do the two differ ? 



9. What drives air into the frog's lungs ? What drives it out ? What 

 would happen if the frog were forced to keep his mouth closed for a long 

 time ? if he were forced to keep it open ? Why ? 



10. How does the breathing system of the frog resemble that of man ? 

 How do the two differ ? 



IL How does the breathing of the frog resemble that of the fish? 

 How do the two differ? 



12. How does the breathing of the frog resemble that of the bird? 

 How do the two differ ? 



13. In what ways is the skeleton of vertebrates like the skeleton of 

 invertebrates ? In what ways are they different ? 



14. How does the heart of the frog resemble that of man ? How do 

 they differ ? 



15. What vertebrates have hearts most like man's? least like man's? 



16. In what ways is the mammalian skeleton hke that of the frog? In 

 what ways is it different ? 



17. In what ways is the skeleton of man like that of other mammals ? 

 In what ways is it different ? 



18. What changes take place in the human skeleton during the period 

 of development ? 



19. What are the particular dangers to the skeleton during infancy? 

 during childhood ? during later life ? Why ? 



20. What connections are there between posture and feelings ? be- 

 tween posture and health ? between health and emotions ? 



21. Why should we have chairs and desks of different sizes at home, 

 in school, and in offices ? 



22. What is the use of X-ray machines in treating broken bones ? 



23. What besides discom.fort may result from having one leg longer 

 than the other ? 



24. What is the advantage of a large muscle development ? What is 

 the disadvantage? 



25. What connection is there between muscle activity and breathing ? 

 between muscle activity and heartbeat ? between muscle activity and 

 excretion ? between muscle activitv and bowel action ? 



