Chlorophyll is the primary green pigment responsible for plant color. the molecule appears green because it absorbs all wavelengths of light except for green, which it reflects back for us to see. in the autumn, trees and plants undergo changes in their pigments. which of the following best describes why we observe many trees change their color to red, orange, or yellow in the autumn? a. as chlorophyll becomes colder, it changes its color from green to red, orange, or yellow. b. chlorophyll breaks down, exposing other pigment molecules we normally don't see. c. the soil produces different nutrients in the winter that are absorbed into the plant and cause color change in the leaves. d. tree leaves stop producing chlorophyll in cold temperatures and produce other pigment molecules.