Answer:
There was a lot of exchange of diseases.
Explanation: "European people also brought diseases, like smallpox, to the Americas. The rats from European ships brought other diseases. Americans who caught these diseases died from them because they had no immunity—their bodies did not know how to fight off the germs."
Cited from https://lsintspl3.wgbh.org/en-us/lesson/midlit11-soc-splcol/6#:~:text=Not%20every%20part%20of%20the,to%20fight%20off%20the%20germs.
