Answer:
Disease helped European expansion into those areas
Explanation:
For example, disease like smallpox was a major contribution to European expansion in the Aztec and Incan empires.
The Aztecs and Incas had no natural immunity to the disease and were extremely vulnerable to it, so smallpox was able to demolish the populations.
The conquerors, Hernan and Cortes, were able to easily crush the populations that had already been weakened by disease.
This was also present in other areas in the Americas and the Pacific.
