Why since the era of the earliest so societies have population centers sprung up in Coastal regions and river valleys?

What happened when Pericles inaugurated a great building program in the Acropolis? The Kiowa seem to have come from and reached their cultural peak on? When a plastic comb is rubbed with a piece of animal fur and is brought close to a fine stream of water from a tap the stream of water will be? Is six flags open on Columbus Day? What did the Alcatraz smell like? The strait of Gibraltar separates which African country and which European country? Is the Atlantic ocean in the US? How wide is the mouth of the Amazon? What is an example of a community in the amazon rainforest? What are the lakes in Nicaragua? What mall has the largest roller coaster at in the mall? What is the distance from Traverse City Michigan to Yosemite National Park? Who opened London Bridge? What were achievements of shi Huang di? Who found 56 holes surrounding the Stonehenge? Why is coral a living creature? How long is the longest piece of snot? Why do kings live in castle? How did Pinckney's Treaty make it easier for settlers in the Trans-Appalachian West to get their goods to market? Main source of carbon dioxide in the ocean?

Why since the era of the earliest so societies have population centers sprung up in Coastal regions and river valleys?