Why is the current the driving force of streams?
a) it carries aquatic life to where the nutrients are.
b) it mixes the nutrients and gases within the system.
c) it regulates the temperature of the stream.
d) it breaks down trash.

Which of the following is a cost of urbanization? a-cities can provide a high standard of living. b-cities are hubs of entertainment and education. c-paving over land changes the environment. d-job opportunities are greater in urban centers.

Which locations on the map are low-pressure areas? a b c d e

When an object is moving away from you while still making a sound, the pitch of the sound is perceived to a. lower b. unchanged c. fluctuating d. higher