What is the importance of the Michelson-Morley experiment?

Question:

What is the importance of the Michelson-Morley experiment?

Light:

Light is electromagnetic radiation of wavelengths lying between 400-700 nm region.

Light have constant speed in vaccume and its value is {eq}\displaystyle{ c=3 \times 10^{8} \ ms^{-1}. }{/eq}