Answer:
These diseases wiped out many of the Indigenous people who lived in the Americas. They had never been exposed to these and were very weak against them. However, Africans had already been exposed to Europeans years prior. They have built up resistance to these diseases. So, Europeans began to ship out Africans to the Americas because they could work and not fall susceptible to European diseases like the Indigenous did.
Spain wanted to protect its colony in Mexico from other Europeans
