Answer:
Electromagnetic waves
Explanation:
Electromagnetic waves are waves that consist of oscillating electric and magnetic fields, that oscillate perpendicularly to each other and perpendicularly to the direction of propagation of the wave (for such a reason, these waves are also called transverse waves).
Electromagnetic waves always travel in a vacuum at the same speed, called speed of light:
and they are classified into 7 different types, according to their frequency. From lowest to highest frequency, we have:
Radio waves
Microwaves
Infrared
Visible light
Ultraviolet
X-rays
Gamma rays
Therefore, gamma rays, x-rays, visible light and radio waves are all types of electromagnetic waves with different frequencies.