What is the main source of air pollution in the united states? list 3 examples.

Apopulation of black bears depends on salmon from a stream for food. if a drought causes the stream to run dry one year, how will this likely impact the black bear population?

How do you know that the plant cells in these two images have different jobs, or functions? a. because all plant cells serve different functions b. because they are two different colors c. because their dna are different d. because their structures are different

49 ! how are energy cycles and growth cycles related?