单项选择题

People in a large area may possess the same DNA thread because ______ .

A．DNA is characteristic of a region
B．they are of common ancestry
C．DNA has the ability to identify individuals
D．their unique identification can be provided via DNA

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热门试题

单项选择题

If two men suspected for some reason they have a common ancestor, ______ .

A．we can decide according to their family tree
B．we can find the truth from their genetic markers
C．we can compare the differences in their Y chromosome
D．we can look for written records to prove their relationship

单项选择题

The author admits that ______ .

A．baseball is too peaceful for the young
B．baseball may seem boring when watched on TV
C．football is more attracting than baseball
D．baseball is more interesting than football