How did trench warfare lead to the development of weapon technology during WWI?
Besides the above on tanks, you could also summarize very simply that it was the development of weapon technology *before* the war which led to trench warfare — large advances in firepower were not matched by large advances in mobility, so the troops were stuck where they met and had to dig trenches to shelter in. I believe that underground mines (the explosive kind, not exploitative kind) and the flamethrower were also developed to new peaks during the war, since they had certain advantages in countering entrenched forces.
