Rivers

-Rivers are usually formed by the runoff of water from the tops of mountains. Gravity pulls it down the mountains and across land, where it eventually reaches sea level and flows into the ocean or a lake.
- Rivers can be helpful to people by means of transportation. Boats can be used to save time instead of walking, or to get to otherwise unreachable places.
- Rivers are home to many types of fish, which are a food source for people.