Why do the benefits of canals and dams not reach everywhere?

Explain how salt content an estuary changes constantly? What countries do tsunamis occur in? How does the Colorado river have not enough water for the animal that live in the Colorado river? What characteristic of the Suez Canal route made it a difficult place for workers to work? How long was frank lee Morris in prison? What new advances helped Europeans feel comfortable about sailing long periods of time in uncharted seas? What makes the pitch lake a place a place of interest for both local and foreigners? What are facts about the Appalachian region? What are some of the secondary consumers in the tropical rainforest? How many days would it have taken to process the population of Albany in 1850 at Ellis island if 5000 people were processed each day? How did Alcatraz get water? What is the worlds largest salt lake in Asia called? Why do rivers start from mountains? What do scientist think the Stonehenge was us for? Is monsoon responsible for rain all over world? How can sound travel through phones? Where is high force falls located? How do you sanitize your mouth? Is there a river in chisinau? What percent of the world has trees?