Strategist, without strategy, this country would be a country
Yes, generally speaking it is true that England began to tax the colonies heavily to help pay for the French and Indian War, which was one of the things that eventually led to the American Revolution.
The correct answer is that they have built up immunities!
The illnesses which lead to the death of many native Americans have been present in the old world for a long time already that many people have already died from them. Those that didn't die were immune and passed on this immunity to their children.