| A | B |
| vegetation | plant life in a region |
| water vapor | water in the form of a gas |
| water cycle | process by which the earth's water moves from the oceans to the air to the land and back to the oceans |
| evaporation | process in which water from oceans, lakes, and streams is turned into a gas or vapor |
| condensation | process in which water vapor changes into a liquid form |
| precipitation | water that falls to the earth as rain, snow, or sleet |
| groundwater | water stored in rock layers beneath the earth's surface |
| aquifer | underground rock layer that stores large amounts of water |