Question 1
For most people, the greatest radiation risk leading to cancer is
◦ medical and dental X rays.
◦ cosmic rays.
◦ radon gas.
◦ sun exposure.
◦ nuclear reactors and radioactive wastes.
Question 2
Half of all cancers are caused by
◦ viruses.
◦ bacteria.
◦ immune suppressing drugs.
◦ environmental factors.
◦ medications.