A scientist separates plant pigments from leaf, root, and stem samples by paper chromatography. All the leaf chromatographs include yellow green and blue green spots but none of the root and only a few of the stem chromatographs have these green spots. Many of the samples have yellow, orange, red, or purple spots.

Question

What is the scientist trying to do/learn?

I was thinking about the chlorophyll.. but i had no ideas on the last sentence "Many of the samples have yellow, orange, red, or purple spots."..

Any help will be appreciated.
Thank You =]