Answer:
The answer should be: Companies replaced hand-operated brakes with air brakes on trains.
Explanation:
You have to think how hard it was for trains to stop with hand operated brakes. Trains go fast, and not stopping in time can be dangerous. Hope this helped :)
He was a French historian and political scientist who championed "uniquely American" values such as egalitarianism.
I believe Kennedy implies this because starting a nuclear war would in the end kill everybody and their would be absolutely no reason to do one.
<em>Hope this helps, Kam</em>
