1 - The flow of the river may change as water is fed out into tributaries. 2- As a river flows it may etch out the river bed and create a gulley as it moves sediment and debris. 3- Depending on the speed of a stream it can form into a meandering river with twists and turns. What is interesting about these rivers is they actually move as debris is deposited on one side of the meander and picked up on the other. 4 - Depending on topography the river may increase in speed and give you rapids.
Longitude: the angular distance of a place east or west of the meridian at Greenwich, England, or west of the standard meridian of a celestial object. This is usually expressed in degrees or minutes.
Latitude: A coordinate that specifies the north–south position of a point on the Earth's surface. Latitude is an angle which ranges from 0° at the Equator to 90° at the poles. Lines of constant latitude, or parallels, run east–west as circles parallel to the equator.
The strip of land that became the site of the Sumerian and the Babylonian civilizations (between Tigris and Euphrates) was known as the Fertile Crescent
