What do Napoleon, Clinton and Wang Nan have in common? They are all left-handed. Today about 15% of the people are left-handed. But why are people left-handed? The answer is the way the brain   works. The brain has two halves---the right half and the left half. The right half controls   the left side of the body, and the left half controls the right side of the body. So right-handed people have a strong left brain, and the left -handed people have a strong right brain. The two halves of the brain are about the same size. But each side controls different things. The left side controls language, Maths and logic  . When you remember new words, or when you put things in order, you use your left side. The right side of the brain controls colour and music. It is also good at recognizing   faces. This does not mean that all artists are left-handed and all accountants   are right-handed. Some right-handers have a strong right brain, and some left-handers have a strong left brain. Whether people are right-handed or left-handed is mostly decided by   _  .
their parents their minds the way the brain works the way the head works