Question

Which economic reason was used to justify the rapid expansion of European colonies throughout the world between the 17th and 19th centuries

Answer 1

That economic reason would be that by gaining control over as much land as possible, Europeans could establish cheap sources of raw materials for the production of finished goods.
This was their reasoning as to why they expanded their colonies greatly during the 17th, 18th, and 19th century. However, they just wanted more territories and more money, as any nation does.