Cold dense air near the pole sinks. it moves toward the equator and is heated, then rises. the warm air then moves back to the poles where it is cooled and sinks again.
what causes these differences in air temperature on earth?

For 50 points populations within ecosystems can be separated into categories—producers, consumers, and decomposers. these categories represent a. the fossil records of organisms. b. the reproductive methods of organisms. c. the body plans of organisms. d. the functions that organisms serve.