The term race or racial group refers to dividing the human species into groups. The most widely used human racial types are those based on visual traits (such as skin color, cranial, facial features, or type of hair). Modern biology says that there is only one human race. But the word "race" also has a meaning in sociology. Many people react in one way if they see a white person and in another way if they see a black person. That's why in the United States and other countries official forms sometimes ask people to describe their ethnic origin. This is a way of saying "what racial group do you think you are?".