1. What is muscle? How much of your body weight is made up of the muscles? 2. What two kinds of muscles are there? 3. How do muscles change in shape? 4. What do we mean by voluntary and involuntary muscles, and how do they differ in form and location? 5. Describe the way in which the body muscles are arranged. What kind of actions do they perform? 6. What exercise is good for the muscles over the abdomen? for the muscles of the back? 7. What muscles are we using when we "bat" or "serve" in ball and tennis? 8. How do the muscles of the limbs act for you? 9. Where are the biceps and triceps muscles? Explain their use. 10. What are tendons? What is their use (function)? 11. How is your arm fastened to your body? 12. Describe the arrangement of the muscles in the lower limb. Why are they larger than the arm-muscles? 13. How does exercising the muscles give you an appetite? What else does it do? 14. Why do you naturally love to play? 15. Why is muscular exercise in the open air important in education? CHAPTER XIX 1. What are the bones? 2. Make a rough sketch of the human skeleton. 3. In what sense are the bones the tools of the muscles? 4. How are the bones of the skull arranged? 5. Give two functions (uses) of the spinal column (back bone). 6. What bones and tendons do you use when you stand on tip-toe? 7. How are the limbs fastened to the body and back bone? 8. Why is the collar-bone more likely to be broken than some of the other bones? 9. How are the joints formed? 10. What is cartilage? 11. How does it help in making the two kinds of joints we find in the body? 12. Is there any arrangement for oiling the joints? If so, what is it? 13. When you soak a bone in weak acid, what happens? What does this prove? 14. What causes disease or deformity of the bones? CHAPTER XX