The answer is C. because they descibe federalism as the combining of multiple gov.s
Here are some of the weapons first used in WWI. Airplanes, Derigables, poison gas, flamethrower, and tanks. Other weapons that were invented before the war but not used on a wide scale or were not reliable until WWI were the machine gun, submarines, torpedoes, small mortars and very large caliber artillery. WWI also saw the use of the radio for the first time in combat conditions.
The United States acquired Puerto Rico, Guam, and the Philippines as territories.
