Preference for using the right or left hand. Some 90 per cent of adults use the right hand for writing; two thirds prefer the right hand for most activities requiring coordination and skill. The others are either lefthanded or ambidextrous (able to use both hands equally well).
Handedness is related to the division of the brain into 2 hemispheres, each of which controls movement and sensation on the opposite side of the body.
In most right-handed people the speech centre is in the left brain hemisphere.
Inheritance is probably the most important factor in determining handedness.... handedness
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