What is the different between Race and ethnicity

ethnicity: identity with a group of people that share distinct physical and mental traits as a product of common heredity and cultural traditions

race: identity with a group of people descended from a common ancestor

One distinct difference is that you cannot change your race, it is the features you carry (eg. skin complex, color of hair, built, and more). However, you can somehow change your ethnicity. For example, you are a Caucasian(race) who was born and brought up in Hong Kong who celebrates chinese new year and believes in Buddaism like a Chinese(ethnicity).