About 4,000 years ago, what did Mesopotamians use to make wheels lighter?

Sleeping sickness in Africa is spread by the tsetse variety of which insect? About 36,000 feet down you'll find the world's deepest spot in which trench, southwest of Guam? Many 1960s baby boys got which name, whether or not they "rowed the boat ashore"? About 4,000 Cherokee died on which forced march in the late 1830s? About 40,000 men were left in which French port after the last evacuation ship left on June 4, 1940? About 57,000 square miles, which is the smaller of the two countries that share Mount Everest? NL is the international vehicle registration code for which country? About 60 members of the Sons of Liberty dressed as Indians for which December 16, 1773 incident?