Was trench warfare an effective method of fighting a war?

Hi Basically they were used as shelters here is something I had in one of my lessons

Explanation:

Trenches provided protection from bullets and shells, but they did carry their own risks. Trench foot, trench fever, dysentery, and cholera could inflict casualties as readily as any enemy.

b.unemployment reached nearly 25 percent.

i dont no the claim so it's hard to answer but i think he would go to the people to decide. : ) ; )