All electromagnetic radiation is visible to the human eye. select the best answer from the choices provided
a. true
b. false

The correct answer is

b. False

It's actually the opposite: only a very small part of the electromagnetic spectrum is visible to human eye.

The electromagnetic spectrum consists of a huge range of wavelengths, spanning from gamma rays (with very short wavelength, at the order of 1 pm) to radio waves (with very long wavelength, at the order of kilometers). The only portion of this spectrum visible to the human eye is the "visible light", which has wavelengths between 400 and 700 nanometers approximately.