Naval Bases and Refueling stations. Hope that helped :)
Answer:
I believe you are talking about the Panama Canal, and if so...
Explanation:
The Panama Canal changed world transportation by cutting the length of traveling around South America from thousands of miles to 50 miles.
Answer:
The three most important rivers areThe Indus River, the Gangus River and the Brahmaputra River.
The volcano adds heat to the hydrosphere