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Joints and Muscles
S
ome parts of the body are quite flexible. Others move only a little.
That’s because there are different types of joints in different places.
There are more than 200 joints in the human body. Each has its
own job to do. The shape of a joint determines exactly how that part of
the body will move. In general, the less movement a body part has, the
stronger that part of the body is.
A slippery, smooth tissue covers the ends of the bones where they meet
and touch. This tissue is cartilage. The cartilage, kept slippery by a special
fluid, allows the bones to move against one another with less rubbing.
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