President Truman had the urge to use the atomic bomb against Japan because the American casualties would continuously rise unless the Empire of Japan surrenders. The thing that would make Japan surrender would be a cataclysmic event, and the bombing of Hiroshima and Nagasaki happened.
Russia was called The Soviet Union in the past when they were communists
The Triple Alliance and Triple Entente are two opposing alliances that triggered in the start World War I. The formation of these two alliances heightened the tensions between European countries. The Triple Alliance which is composed of <span>Germany, Austria-Hungary, and Italy had a conflict with Triple Entente members - France, Russia, and Great Britain. Germany and Russia, during that time, had a great interest towards the Balkans. This is one of the reasons of the occurrence of World War I. So, the answer to the question is letter d. increasing tensions between European countries.</span>
Those tools that had been preserved, of course, are the stone tools. Paleoindian stone tools were generally made from workable stones like chert, quartzite, or obsidian, and Paleoindians seem to have been very picky about only using the best materials for their tools.
I got this from here ⇒ Paleo Indians: Culture, Artifacts & Tools | Study.com
Hope this helps you! =^-^=