Answer
Ionizing power: Gamma rays, Beta particle/Positron, Alpha Particles
Penetration power: Alpha particles, Beta particle/Positron, Gamma rays
Work Step by Step
Because alpha particles are so big, they can do a lot of damage but are easily shielded against. Alpha particles can be very dangerous if ingested however. Positrons and beta particles are about the same and ionizing end penetration power. Their penetration power is more than an alpha particle but there are not using power is less. Gamma rays are very high energy and therefore do not interact as much as the other forms of radiation. This means they can pass through more shielding but have lower ionizing power.
