What did europeans bring with them to the americas that is considered by many to have made the europa conquest and colonization the americas possible

The diseases such as smallpox were brought to the Americas by Europeans and it helped them to conquered Americas. They didn't had to use the weapons because the diseases which were common among Europeans wrecked havoc among the natives. The native Americans have been isolated for too long and never came in contact diseases like small pox, hence they  never developed resistance against it and when they came in contact with these diseases for the first time, they started to die in large numbers.

the answer is: the sesquicentennial of the american civil war is an occasion to consider the legacy of that great conflict. this legacy is our inheritance, and despite many indelible features, we continue to negotiate the resolution of that conflict. the civil war was fought over slavery, but not always on behalf of slaves