Answer:
gamma rays
Step-by-step explanation:
Electromagnetic waves is a propagating medium used in all communications device to transmit data (messages) from the device of the sender to the device of the receiver.
Gamma rays is a type of electromagnetic waves that are dangerous enough to be used to kill cancerous cells.
In the electromagnetic spectrum, gamma rays are known to have the greatest amount of energy and shortest wavelength among the wave particles. They are generally produced through the disintegration of radioactive elements.