Answer:
Seven waves make up the electromagnetic spectrum.
Step-by-step explanation:
Radio Waves
Used in television and radio broadcasts
Microwaves
Used for satellite communications and heating up food
Infrared radiations
Used in electric heaters and other heating devices.
Visible light
used for fibre optic communications
Ultraviolet rays
used in energy-efficient lamps, sun tanning
X-rays
Medical imaging and treatments
Gamma rays
used for sterilizing and disinfecting
Wavelengths down the spectrum increase as the frequency decreases.