Question

for the most common types of nuclear decay, the order of least dangerous to most dangerous is gamma, alpha, beta gamma, beta, alpha beta, gamma, alpha alpha, beta, gamma

Explanation:

Alpha particles have the least penetrating power and can be stopped by a sheet of paper or the skin. Beta particles can penetrate through paper but are stopped by a thin layer of metal. Gamma rays have the highest penetrating power and require thick lead or concrete to be significantly attenuated. So the order from least dangerous (least penetrating) to most dangerous (most penetrating) is alpha, beta, gamma.

Answer:

alpha, beta, gamma