What new weapons or improvements on old weapons made the Civil War the deadliest war in U. S, history?

Machine guns and repeating rifles

Explanation:

Machine guns were used in the Civil War. Compared to the powder muskets of the revolutionary war, These guns didn't need to be reloaded as often and as a result could inflict more casualties on the opposing side. They were also an all around improvement, with better accuracy then their primitive counterparts.

a.  

women in ancient egypt had many legal rights, including the right to own property and businesses.