EXERCISE INI Write a brief argument to explain each of the following. Indicate what facts and what general principles are employed in your explanations. (Do not forget those principles that may seem too obvious to mention.) 1. Why a lighter-than-air balloon rises. 2. Why there is an international date line. 3. Why average temperatures tend to be higher closer to the equator. 4. Why there are usually more college freshmen who plan to go to medical school than there are seniors who still plan to go to medical school. 5. Why almost no textbooks are more than eighteen inches high. 6. Why most cars have four tires (instead of more or fewer). 7. Why paintings by Van Gogh cost so much. 8. Why wages go up when unemployment goes down