a. Everyone is exposed to low levels of radiation. What are two sources of this background radiation? b. Name one adverse health effect that is linked to exposure to background radiation. a. Which is...

a. Everyone is exposed to low levels of radiation. What are two sources of this background radiation? b. Name one adverse health effect that is linked to exposure to background radiation. a. Which is most easily shielded against, alpha particles, beta particles, or gamma rays? b. Which of the types of radiation in part a is the most difficult to shield against?