It's important that we know where and how we came to be. For example we wouldn't really understand why you're a certain religion if we didn't know who settled the land and what happened. Not only that, but also a lot of things happened back then, a civil war, WWI and WWII, the Cold war, war of 1812, that made things what it is present day. Also history makes sure that we can honor people for freedom, such as Abe Lincoln who freed slaves. The point I'm making here is that history is a way to remember important events that have effected many things and many places and without keeping track of history (for example if we didn't keep track of the Constitution) we wouldn't have the somewhat peaceful society of today.
To prevent the spread of communism to the south Vietnam
1.desert
2. tropical
3.savannah
4.rainforest
5. Mediterranean
*Wild guess*
WWI changed the face of warfare forever. Warfare became utterly impersonal with the invention of the tank, fighter airplane and automatic machine gun. The allied powers emerged victorious and powerful, both economically and militarily. The German Empire, on the other hand was utterly decimated, culturally, militarily, and economically. WWI lead to a halt in imperialistic policy and the formation of the League of Nations, the ineffective predecessor to the United Nations. The main end result of WWI was Adolf Hitler's rise to power and WWII.