A、It can’t be stopped but can be reversed. B、It can’t be reversed but can be slowed. C、It can’t be slowed but can be reversed. D

When we say older people shrink, we don’t mean they become tiny enough to fit in your pocket! We just mean that it’s common for older people to become a little shorter over time. It isn’t dramatic or sudden. It takes place over years and may add up to only an inch or so off of their adult height.(19)This kind of shrinking can’t be reversed, although people can slow or stop this process. But why does shrinking happen at all?
    Gravity, the force that keeps your feet on the ground, takes hold, and the disks, or cushions between the bones in the spine, get compressed over time.(20)The back bones end up pressing closer together, which makes a person lose a little height and become shorter.
    Another reason why some older people shrink is because of the weakening of the bone which occurs when the bone is broken down and not enough new bone material is made. Over time, the bone is said to be lost because it’s not being replaced. Bones become smaller and weaker and can easily break if someone with this problem is injured.
    Older people, especially women, who generally have smaller and lighter bones to begin with, can get small breaks in bones that are called compression fractures.(21)These breaks cause collapse of the back bones and over time the person can become stooped.
19. What do we know about the shrinking process of older people?
20. What is the main reason for people’s becoming shorter?
21. How do people become stooped?