Complex sentence: A number of different systems of classification of ethnicity in the United Kingdom exist.This scheme has been the subject of debate, including about the nature of ethnicity, how or whether it can be categorised, and the relationship between ethnicity, race and nationality.
Split into simpler sentences: A number of different systems of classification of ethnicity in the United Kingdom exist. These schemata have been the subject of debate, including about the nature of ethnicity, how or whether it can be categorised, and the relationship between ethnicity, race and nationality.