Identify one factor that led to the downfall of land based empires in the era of 1450-1750.

Imperial expansion in Europe and Asia resulted from the increased use of gunpowder, cannons, and armed trade to establish large empires. Most of the groups that were conquered were weak or disorganized. These land based empires included the Manchu in Central East Asia, the Mughal in South and Central Asia, the Ottoman in Southern Europe, the Middle East and North Africa. The rulers centralized their power over politics, religion and the military. They also controlled trade, enriching the rulers, who created cultural monuments and stronger militaries.

this is a good question! i'll do some research and come back when i have the answer!

the speech revealed that eastern european countries were no threat to their neighbors, which led to the creation of the truman doctrine i think this might be correct.