Which was NOT a new weapon introduced during WWI?

atomic bomb
airplane
poison gas

Atomic Bomb

Explanation:

The airplane had made its way as a machine of war in WW1 and chemical warfare was also used such as, "Mustard Gas." The Atomic bomb was not developed till the late stages of WW2.

the answer would be option c. the chief result of u.s. participation in world war i is that, the u.s. forces ended the stalemate and led to an allied victory. after the us joined wwi, the allies had the forces they need to triumph. hope this is the answer that you are looking for.

explanation:

mark brainliest and have a great day!

i think the answer is c, rivers.

explanation:

sometimes, borders fall along natural boundaries like rivers or mountain ranges. for example, the boundary between france and spain follows the crest of the pyrenees mountains. for part of its length, the boundary between the united states and mexico follows a river called the rio grande. the borders of four countries divide africa’s lake chad: niger, chad, cameroon, and nigeria.