What is the source of natural carbon-14?
A. nuclear fission of the heavy, radioactive elements uranium and thorium
B. fusion of hydrogen and helium in the Sun and eruption of solar flares
C. leakage of radioactive gases from the liquid, outer core
D. cosmic ray collisions and neutron-capture involving atmospheric nitrogen
Answer:D
What is the source of natural carbon-14?
A. nuclear fission of the heavy, radioactive elements uranium and thorium B. fusion of hydrogen and helium in the Sun and eruption of solar flares C. leakage of radioactive gases from the liquid, outer core D. cosmic ray collisions and neutron-capture involving atmospheric nitrogen