题目内容：
根据以下材料，回答题。
A. They end up pressing closer together，which makes a person lose a little height and become shorter.
B. That's because as the day goes on， water in the disks of the spine gets compressed (squeezed) due to gravity，making you just a tiny bit shorter.
C. Over time，bone is said to be lost because it's not being replaced.
D. Luckily，there are things that people can do to prevent shrinking.
E. For older people，shrinking isn't that dramatic or sudden at all.
F. There are a few reasons.
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