How racial distinctions change over time and place

Racial is modern word direct towards physical, biological, cultural and social and ethical variations. Intensity of racism followed descending order over time and place.  

Explanation:

Race is social barrier for human development and resulted from incidents, wars, post war significance etc. Biological race developed over time like skin color, facial features and many other physical factors, connected from specific geographical areas and responsible for human group formation. Social and ethical perceptions difference in terms of financial status, citizenship was huge popular while cultural variations like caste, religion exist now also but with low intensity. In USA racism trend established nearly 1789, when white and nonwhite categories were recognized. When U.S decennial census was firstly conducted in 1790 racial classification involved whites, American Indians while all slaves were treated as blacks.  UNESCO established in 1945 and rejected all theories regarding racial hierarchies. In 1978 UNESCO published “Declaration on Race and Racial Prejudice” and included Apartheid as racism example.

productive most commonly means: achieving or producing a significant amount or result.

explanation:

productive can also mean:

these depend on how the word productive is used. most likely productive will mean   achieving or producing a significant amount or result.