7. Like marrying like

　　Just as people pair off according to looks, so they do for size. Lean people are more likely to marry lean an d fat more likely to marry fat. On its own, like marrying like cannot account for any increase in obesity. But combined with others —— particularly the fact that obesity is partly genetic, and that heavier people have more children-it amplifies the increase form other causes.

　　1. What is the passage mainly about?

　　A) Effects of obesity on people’s health

　　B) The link between lifestyle and obesity

　　C) New explanations for the obesity epidemic

　　D) Possible ways to combat the obesity epidemic

　　2. In the US Nurses’ Health Study, women who slept an average of 7 hours a night _______.

　　A) gained the least weight

　　B) were inclined to eat less

　　C) found their vigor enhanced

　　D) were less susceptible to illness

　　3. The popular belief about obesity is that _______.

　　A) it makes us sleepy

　　B) it causes sleep loss

　　C) it increases our appetite

　　D) it results from lack of sleep

　　4. How does indoor heating affect our life?

　　A) It makes us stay indoors more

　　B) It accelerates our metabolic rate

　　C) It makes us feel more energetic

　　D) It contributes to our weight gain