In order to assess your understanding of the lesson materials, please select the most appropriate answer for each of the multiple choice questions below.
    Question 1/3

    What is the primary mechanism for helium production on earth?

    1. A
      Fusion of hydrogen atoms
    2. B
      Radioactive decay of heavy radioactive elements such as uranium and thorium
    3. C
      Radioactive decay of lighter radioactive elements such as potassium-40
    4. D
      Produced by heat and pressure acting on organic-rich sediments