What made europeans in the americas realize that they needed a new workforce in the early 1500s?

They realized that they did not have enough people to do all of the work of establishing a colony. That's hard work, for like 400 people! This sparked the massive slave trade of the 1500 slave trade. 

If this helped, please rate, thank, and give brainliest answer (over that dude who commentated asdf."

Ibelieve the answer is answer 5