What will man be like in the future --- in 5,000 or even 50,000 years from now? We can only make guesses, of course, but we can be sure that he will be different from what he is today, because man is slowly changing all the time. Let us take an example. Man, even five hundred years ago, was shorter than he is today. Now, on average , men are about three inches taller. 500 years is relatively  a short period of time, so we may suppose that man will continue to grow taller. Again, in the modern world we use our brains a great deal. Even so, we still use only about 20% of the brain's capacity . As time goes on, however, we shall have to use our brains more and more, and finally we shall need our brains more and more, and finally we shall need larger ones! This is likely to bring a physical change too. The head, especially the forehead , will grow larger. Nowadays our eyes are used too much. In fact, we use them so much that very often they become weaker and we have to wear glasses. But over a long time it is possible that man's eyes will grow stronger. On the other hand, we make use of our arms and legs less. These, as a result, are likely to grow weaker. At the same time, however, our fingers will grow more sensitive  because they are used a lot in modern life. But what about hair? This will probably disappear from the body because it does not serve a useful purpose any longer. In the future, then, both men and women are likely to be hairless. Perhaps all this gives the impression that future man will not be a very attractive  person to look at! This may be true.However, future man will still have a lot in common with us. He will still be a person, with thoughts and feelings similar to our own. The passage mainly tells us that   _  .
man's life will be different in the future future man will look different from us man is growing taller in the future man is changing quickly all the time