This would be called a mutation because it stated above neither of it's parents have it so say for humans both parents have 2 arms which is normal. They have a child and he/she only has one arm thus mutation.
As shown in detail in the absorption spectra, chlorophyll absorbs light in the red (long wavelength) and the blue (short wavelength) regions of the visible light spectrum. Green light is not absorbed but reflected, making the plant appear green
