Race is classification of humans into distinct populations or groups by factors such as heritable phenotypic characteristics or geographic ancestry. This often influenced by and correlated with traits such as appearance, culture, ethnicity, and socio-economic status.
In the beginning of last century the term race was often used, in its taxonomic sense, to denote genetically divergent human populations which can be marked by common phenotypic traits. This is still used in our day for forensic anthropology (when analyzing skeletal remains), biomedical research, and race-based medicine as proxy for geographic ancestry with some reliability. In addition it is used in law enforcement to describe the closest picture of wanted suspect.
Human classification on the basis of physical traits is difficult because factors such as invasions, migrations, and mass deportations have produced a heterogeneous world population. Nevertheless, by limiting the criteria to such traits as skin pigmentation, colour and form of hair, shape of head, stature, and form of nose, most anthropologists historically agreed on the existence of three relatively distinct groups: the Caucasoid, the Mongoloid, and the Negroid. “Criticism of the idea that there are clearly recognizable racial types does not imply that all human populations are uniform or that population cannot be grouped into larger units that, among themselves, have certain similarities” James C King (1981).
The Caucasoid is characterized as pale reddish white to olive brown in skin colour, of medium to tall stature, with a long or broad head form. The hair is light blond to dark brown in colour, of a fine texture, and straight or wavy. The colour of the eyes is light blue to dark brown and the nose bridge is usually high and found in Europe, N Africa, and the Middle East to N India, The Mongoloid race has been described as saffron to yellow or reddish brown in skin colour, of medium stature, with a broad head form. The hair is dark, straight, and coarse; body hair is sparse. The eyes are black to dark brown. The epicanthic fold, imparting an almond shape to the eye, is common, and the nose bridge is usually low or medium and they live in East Asia and the indigenous peoples of the Americas. The Negroid race is characterized by brown to brown-black skin, usually a long head form, varying stature, and thick, everted lips. The hair is dark and coarse, usually kinky. The eyes are dark, the nose bridge low, and the nostrils broad. To the Negroid race belong the peoples of Africa south of the Sahara, the Pygmy groups of Indonesia, and the inhabitants of New Guinea and Melanesia.
Since the 17th century attempts made to classify humans. Johann Friedrich Blumenbach was the first to divide humanity according to skin colour. “Among the words that can be all things to all men, the word Race has a fair claim to being the most common, the most ambiguous, and the most explosive” Barzun j (1937). In the 19th and early 20th century, people such as Joseph Arthur Gobineau and Houston Stewart Chamberlain, mainly interested in pressing forward the supposed superiority of their own kind of culture or nationality, began to attribute cultural and psychological values to race. This approach called racism. The Oxford English Dictionary defines racism as the "belief that all members of each race possess characteristics, abilities, or qualities specific to that race, especially so as to distinguish it as inferior or superior to another race or races". Racism is a product of capitalism. Herbst (1997) mentions “discrimination is behavior that denies people equal treatment because of their membership in some group”.
To conclude, human classification into different groups depending on their physical appearance is difficult task and might lead to racial division and conflict. Race is like fluid and thus difficult to pinpoint scientifically “Race is a concept of human minds, not of nature,” Relethford writes.

References; * About.com, 2011. Race Relations. [Online] available at: < http://racerelations.about.com/bio/Nadra-Kareem-60956.htm> (Accessed 12/2011). * Barzun J., (1937). Race: a study in modern superstition, London: Methuen & Co .Ltd. * Blink-racism, 2000. Racism’s roots. [Online] available at: <http://archive.itvs.org/blink/racism.htmll> (Accessed 12/2011). * Fox H., (2009). When race breaks out: conversations about race and racism in college classrooms, New York: Peter Lang publishing, Inc. * George T. H., and Alan H. G., (2006). The nature of difference: science, society, and human biology, Boca Raton: Taylor & Francis Group. * Ideasactionblog.org, 2011. Race. [Online] available at: < http://www.ideasactionblog.org/search/label/race.html> (Accessed 12/2011). * King C. J., (1981). The biology of Race, California: California University Press. * Miles R., (1993). Racism after 'race relations', London: Routledge. * Oxford University, 2011. Oxford Dictionary. Oxford: Oxford University Press.