Answer 1:
Good question. Scientists call the human tailbone
a vestigial structure. For monkeys, tails
are an important body part that helps them keep
their balance--this is part of the reason that
they are so good at moving around in the trees.
Scientists think that, near the end of the time
period when humans had tails, they no longer had a
useful function like this. There may even have
been some reason that having a tail was actually a
bad thing, for example for the prospects of
finding a mate or just for surviving. So most
scientists believe that over time, the humans that
were the best at passing on their genes were the
ones that didn't have tails. We call this
evolution: we think that humans evolved to lose
their tails.
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