Which describes an achievement of Emperor Yangdi that helped unite China? A. He made Marco Polo an honored guest at the imperial
court in Beijing. B. He introduced terraced farming to produce more food. C. He designed a plan for a series of interconnecting canals. D. He built the Great Wall of China to keep out invading Mongol hordes.
Island hopping is the U.S. strategy against Japan in ww2. By taking important Pacific islands and building military bases on those islands, the U.S. slowly advanced towards mainland Japan and prepared for invasion.