4. Armored Vehicles/Tanks. 5. Bomber Planes. 6. Man V. Machine 7. Gas. 8. Gas Masks. 9. Artillery. 10. Trench Club
Also, you got things wrong in Number 1 and and 3, Let me fix it :
1. Espionage/Spies 3. No-man’s Land, Because if someone would go through No Man’s Land Alone, they would simply be shot by the Machine Guns mounted in the Opposing Trench.
