When fossil fuels and biofuels are burned, the stored energy in what substance is related to generate electricity? a) neutrons
b) geothermal heat
c) sunlight
d) organic matter

Which is an important function of normal flora? a. aid with bone marrow production. b. crowd out pathogenic bacteria. c. destroy digestive track pathogens. d. manufacture iron in the bloodstream.

12) several teeth were found in an area of flat land covered with trees and plants. the teeth were examined by a paleontologist, and it was determined that the teeth came from a shark. they found many other shark teeth in this area. however, the people who discovered the teeth were puzzled, because there was no source of water near where the fossils were found. what is the paleontologist's best explanation for why the teeth were found in this area? a) sharks used to live on flat land. b) this area was once covered with salt water. c) this area was once covered with freshwater. d) someone buried the shark teeth deep in the ground.

In the 1500s, an astronomer developed a new model of the universe. this model had the sun at the center of the universe, not earth. who was this astronomer?