Grey Scale – to edit the grey scale I went to image/mode/grey scale. Applying Grey Scale gives the image only intensity values, no color values.
Desaturated – to desaturate this image I went to image/adjustments/desaturate. Applying desaturation lowers the intensity of the color.
Monotone – to make this image monotone I converted it to grey scale, then selected duotone and then selected a color. This gives the image only one color.
Channel Mixer – to access channel mixer I added a new layer and then adjusted the RGB values.