1. The author begins the passage by ____.

1. presenting an argumentation
2. explaining a phenomenon
3. raising a question
4. making a comparison

2. The ratio of giving birth to a boy is falling in rich countries because ____.

1. the terrorist attacks of September 11th 2001 exerted huge negative impact
2. women are facing greater pressure than past
3. women are under new pressure now which they seldom faced in the past
4. male pregnancies are more easily to miscarry

3. Which of the following can explain Dr. Obel's opinion that the ultimate cause is adaptive rather than pathological?

1. 47% of children born to women in the top quartile of stress were males while 52% in the bottom quartile.
2. Women in rich countries are more likely to give birth to boys.
3. Women selectively abort boys rather than waste time and resources on bringing them to term for fear of male competition.
4. Women who suffer from calamity in conception are more likely to give birth to girls.

4. Women in the hunter-gatherer societies are more likely to give birth to daughters because ____.

1. they agree that giving birth to daughters is beneficial in the evolutionary sense
2. sons are likely to produce lots of grandchildren with several women
3. they think it is a better practice for a daughter to produce grandchildren with only one mate
4. they think bringing sons to term is wasting time and resources

5. From this passage, we may draw a conclusion that ____.

1. acute stress is more likely to cause women to choose aborting boys than chronic stress
2. stress to a woman at the time of conception, whether acute or chronic, will shift the sex ratio towards girls
3. more girls will be born in the future because today's women, in both rich and poor countries, suffer from increasing pressure
4. chronic stress is more decisive in influencing the women's pregnancies

(Reference keys.)