In the late 1800s, how did european countries build empires?
by settling newly discovered lands
by buying land from other countries
by expanding their existing borders
by taking over other countries

(d) rivers.

explanation:

civilizations developed around rivers because their waters provided places to hunt and fish. also, as the rivers flooded, the lands around them became fertile. this allowed them to support farming. this is especially true of the nile river, which flooded the same time each year.

the difference is that white collar worker performs skills like worker as a scientist or well blue collars do physical work and they do services like being a cook.