Answer:
a) Wavelength .
Explanation:
Visible light is comprised of all the seven colors Violet , Indigo , Blue , Green , Yellow and Red .
Color depends up on the wave length of the light .
For example a red ball appears red because it absorbs wavelengths of all the other colors and reflects only wavelengths corresponding to red color.
That will be A melting a substance that's because the rest are examples of chemical changes and also its the same thing but in a different form.
The weight of the car in the picture of the computer screen is 9,800 Newton's.