They were used for blasting people out of trenches.
The Trench Mortars effected the World War 1 (WW1) by giving an advantage to the users by being able to keep cover and still be able to shoot over and hit or at least hit the ground near the enemy's trenches to force then to move.
They had to duck in a trench or else...
shell shock and trench foot
Well this one seems kind of obvious, but Trench Warfare is called Trench Warfare because the men fought in Trenches during WW1 in which trench warfare was utilized.
fighting in trenches
yes
through trench warfare, and in offensives it would be... barrage, over the top , slaughter.
trench foot also trench mouth was a major killer
a trench
wet
by not getting it