Because the old weapons become to common and considered to be to predictable
Some are
germ warfare
Same reason they always invent new weapons - to help them win. Superior weapons go a long way to help win a war. America has ruled the world because of superior fire power.
GrenadesFlamethrowersTanksMachine gunsPoison gas
Chemical weapons and the machine gun
M16
The new weapons of world war one were machine guns,Tanks,poison gas, and planes og WW1
Tanks
Germany did
Some are
germ warfare
Because the old weapons become to common and considered to be to predictable
in world war 1 Germany introduced the use of chemical weapons for instance the Mustard Gas artillery shells, theses weapons where mainly used by countries on there side.
Same reason they always invent new weapons - to help them win. Superior weapons go a long way to help win a war. America has ruled the world because of superior fire power.
They helped develop new weapons to win the war
Airplanes, poison gas, machine guns and tanks.