Define race and ethnicity. What is the difference between the two?

race is some ones physical characteristics such as eye color or height

while ethnicity is you culture, ancestry and language.

Race has to do with a person's physical characteristics, such as color of skin and eyes, type of hair, etc.; whereby Ethnicity has to do more with the cultural factors of the person, such as language and nationality; in other words ethnicity factors have more to do with culture in a given geographic region.