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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热门试题

单项选择题

The gender of the baby is decided by ________.

A．the father's DNA
B．the mother's DNA
C．the father's sperm
D．the mother's egg

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