The biggest cause of air pollution is: A. factories
B. airplanes
C. buses
D. automobiles

Which of the following is an example of this type of co-evolution

What is true of all organisms in the kingdoms protista, plantae, fungi, and animalia? a. they are multi-celled. b. they are photosynthetic. c. they have cells that contain membrane-bound organelles. d. they contain cells that lack membrane-bound organelles.

Explain the source of radioactivity in uranium in earth’s crust by which it produces nuclear radiation