Which are the 7 races of human beings?

This answer really depends on what you mean by variation. One interpretation would look at humans within a population as individuals. Each individual has their own genetic makeup or code, which gives them subtle differences between other people in the same population. The differences encoded by genetic material result in differences for people in things like: Height Eye colour Weight Hair colour Skin tone Gender 'Tongue-rolling' ability Absence or presence of ear lobes Size of feet There are hundreds of differences between people in their genomes, and these are just a few examples. The second interpretation could look at what makes people individual due to their environmental influences around them. No matter what a person's genome encodes for, it does not completely affect how they will look or differ from others in a population. The environment will affect them in several different ways: Their diet will affect their height and weight Their age will affect how old they look Their hair colour may be changed by dye Changing hair colour with dyes also leads onto another way human populations can vary, by their cultural influences. For instance, people who are born and brought up in the UK may prefer drinking tea than coffee, whereas people born in the USA may prefer American Football to Football/Soccer. Cultural influences are the same as environmental differences, and are a result of a persons upbringing, location or interests. Several places and groups within the world have very well-known characteristics which define them as a population.