单项选择题

Girl sperm was preferred to boy sperm in the research most probably because ______.

A．girl sperm contains more genetic material
B．more mothers want to have girl babies
C．girl sperm is healthier and more active
D．girl sperm is more easily purified
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单项选择题
What is the main idea of this passage
A．Obesity is now a global problem that needs tackling.
B．The weights increase fast throughout the whole world.
C．Obesity and starvation are two main problems in the poor world.
D．Obesity has shifted from the rich world to the poor world.
单项选择题
Which is NOT the point of the example of the Pacific Islands
A．The poor community has shaken off poverty and people are well-fed now.
B．Obesity is becoming a problem in the developing world too.
C．Excessive weight increase will cause no less harm than the food shortage.
D．The problem of overweight emerges very fast.
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