单选题
During recent years we have heard much about "race": how this race does certain things and that race believes certain things and so on. Yet, the【C1】______phenomenon of race consists of a few surface indications. We judge race usually【C2】______the coloring of the skin: a white race, a brown race, a yellow race and a black race. But【C3】______you were to remove the skin you could not【C4】______anything about the race to which the individual belonged. There is【C5】______in physical structure, the brain or the internal organs to【C6】______a difference. There are four types of blood.【C7】______types are found in every race, and no type is distinct to any race. Human brains are the【C8】______. No scientists could examine a brain and tell you the race to which the individual belonged. Brains will【C9】______in size, but this occurs within every race.【C10】______does size have anything to do with intelligence. The largest brain【C11】______examined belonged to a person of weak【C12】______On the other hand, some of our most distinguished people have had【C13】______brains. Mental tests which are reasonably【C14】______show no differences in intelligence between races. High and low test results both can be recorded by different members of any race.【C15】______equal educational advantages, there will be no difference in average standings, either on account of race or geographical location.