A、They prefer left hands to right hands. B、They use both hands before age three. C、They are not allowed to be lefties. D、Their h

Many studies have been made recently about hand preference in human. They have brought interesting results. It has been found, for instance, that many more men than women are left handed; that all children use both hands about equally until they are three years old; and that hand preference is not clearly marked until age six. Above that age, most people not only favor one particular hand, but they also have a favorite eye, a favorite ear and foot.
    We know that the left side of the body is controlled by the right side of the brain. It seems that this particular half is the seat of emotion, imagination, and of the sense of space. And, indeed, lefties seem to be more creative than their right-handed fellow humans; they also seem to be more athletic and to do better in some professions which—like sports—require a good sense of space. In a large school of architecture, it was found in 1977 that 29 percent of the professors and 23 percent of the graduating students were left-handed—while lefties represent less than 10 percent of the general population.
    Lefties manage to drive, to sew, to paint, to use machines as well as any right hander. It is not easy for them, however, to struggle with tools, school desks, automobile and television controls, and many ordinary objects. Fortunately the creation of Left-Handers International has attracted attention to their problems and caused the appearance of special stores offering all sorts of objects for lefties, including wrist-watches, musical instruments, pencil-sharpeners, cameras, scissors, and books that show them how to play left-handed guitar and left-handed golf.
16. What can we learn about hand preference among children?
17. Why does the speaker say lefties do better in sports?
18. What is the purpose of Left-Handers International?