How can the introduction of a new species into an area effect the land, the flow of water, the atmosphere, and/or the other living things?

Amagazine is holding a contest for amateur historians. it plans to publish two articles responding to the following claim: "the united states should never have engaged in proxy wars during the cold war." the magazine will publish one article that supports the claim and one article that opposes it. you'd really like to win both prizes, so you've decided to submit two articles – one supporting each side. each of your articles should use historical evidence to support each position and should discuss at least three instances of proxy wars or u.s. military intervention in different regions of the world.