a. it contributed to the defeat of american indians.
Explanation:
When the spanyards came to america they brought with them diseases that were never seen in this part of the world, because of that the americans never had developed defenses against them, that diminished the population of the indian americans and helped the conquerors to easily defeat and conquer the americans, its estimated tha 70% of the indian population died due to the smallpox and other diseases brought by the spanyards.
