单项选择题

According to this passage, the practice of "sex selection" ______.

A．can help to prevent all genetic problems
B．is totally unacceptable to ethics experts
C．was already realized five hundred years ago
D．will benefit families with certain inheritable diseases

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热门试题

单项选择题

It can be concluded from the passage that the author's attitude toward sex selection is ______.

A．negative
B．positive
C．neutral
D．favorable

单项选择题

The DNA in the sperm cells can be measured ______.

A．in the same way how the cattle are herded
B．when they pass through a tube one behind the other
C．after they pass through a laser tube
D．when they are scanned by a laser detector all at a time