For a living organism, which of the following are true? select all that apply
a the ratio of c-14 to c-12 remains constant.
b the ratio of c-14 to c-12 increases over time.
c the ratio of c-14 to c-12 decreases over time.
d the amount of c-14 is less than the amount of c-12.

How many major plates cover the earth

Which is a function of the central nervous system

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.