Flowing, moving stream of fresh water. They begin at their source called the "headwater" in higher ground such as mountains or hills, where rain water or melting snow collects and forms tiny streams. They flow downhill where the end at their "mouth".

Formed at the mouth of a river as water slows down and loses the power to carry sediment.

Smaller body of water than an ocean. Completely or partially surrounded by land or a chain of islands.

A region that gets very little rain fall per year (less than 10 inches). They can be very hot or very cold.

A series of mountains that are connected together generally to form a long line of mountains. 

A raised area of land that is flat on top with steep cliffs or sides found on every continent and the ocean floor.

An area of land that are not connected to a continent and are surrounded by water.

A region of land with water on three sides.