I'm going to assume that you meant "trenches". They were used to protect soldiers from artillery and/or strafing and bombing. Also they provide cover from enemy fire. Which is harder to shoot, somebody's head or somebody's whole body? They used them in World War two also. It used to be (civil war era) that the opposing sides would just run at each other and shoot. When machine guns were invented that tactic became obsolete. If you watch crime shows then you will see when the cops are getting shot at they duck behind a car or a crate for cover and then when they shoot they just stick their gun and half of their head out. It does the same thing as a trench, but military trenches also defend against artillery and bombs.
To increase public support for the war
water transport
observation balloon
to fight and help the usa become stronger! hope this helps
where is world war 1 come from?how many years a go in world war 1?what is world war 1?how many people dead in world war 1?who is win in world war 1?how many people live in world war 1?when the world war 1 start?how many helicopter they use?when thwe world war fished?
The trench warfare changed the people that lived during the war because they where scared.They was scared because they didnt want to have to go to the war and be in those horrible conditions.And they where scared about there love ones that was in the war
To increase public support for the war
Sending troops to Europe was done for the purpose of creating a strong military in World War 1. There is strength in numbers.
The soldiers would have played with a ball, like a soccer ball and this would be done at the back of the tranches when there was a seize fire (when each soldiers made a temporary treaty)
To simply end the war for world war 1, for world war 2 it was end the war and take down the Nazis
The assassination of Franz Ferdinand (not the band)
water transport
Scouting & sinking ships.
observation balloon
to divide the Ottoman Empire after the war
Hmmm, there were rather more than two.
to destroy enemy ships and to kill allies