Handedness is the idea that one hand is better able to perform certain tasks than the other. The most common answer for people being right-handed is that handedness is determined by the structure of our brains, which are divided into two hemispheres. One theory suggests that it's more efficient for the brain to cluster control of these two major tasks in one hemisphere rather than having it spread throughout the brain. Since the vast majority of people have their language functions centered in the left hemisphere, it follows that most people's fine motor skills would be controlled by the left hemisphere too. Each hemisphere generally controls the opposite side of the body, so the end result is that most people are right-handed. In humans, the hemispheres tend to specialize: Nearly all righties process language in the left side of the brain, while many lefties process language on the right. Aga, thisis just a proposed theory, the reasons still being explored. :)