Fossils in precambrian rocks are rare, while there are many fossils in rocks from the phanerozoic eon. what does this evidence suggest? a. there was a major change in the diversity of life in the phanerozoic eon, probably due to mass extinction. b. there was no life in the precambrian eon. c. the rocks from the phanerozoic eon are much harder than those from the precambrian eon. d. there was no change in the diversity of life in the phanerozoic eon.

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.