The correct options are
A Gamma rays have the highest penetrating capacity
B Gamma rays can cause both external and internal damage to body tissues
D Beta rays can cause skin burn
Different rays have different penetrating capacities. Alpha and beta particles have lesser penetration power than gamma radiations. Alpha particles cannot penetrate skin but can cause harm if ingested or inhaled by accident. Beta particles can penetrate a few centimetres of skin and can pose external health risks like superficial burns to the skin on high levels of exposure. Gamma radiations however, can penetrate the body and can cause damage to internal tissues and organs.