Which resulted from both world war I and world word II

a lot of fatalities

Explanation:

greed, the need for nationalism and imperialism caused a lot of havoc which resulted to the wars and a large number of people were killed like never before

four sitting presidents have been assassinated while in office but the first was abraham lincoln,

answer: the time zones used to be whatever the local authority wanted them to be. one town might have 6am whenever the sun came up and another town had 6am 10 minutes later.  

the trains had a hard time when their orders said to be at a certain point at 6am.  

6am, but who's 6am.  

the railroads got together and set the time zones more or less along the longitude lines across the country.

explanation: