Question

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.

Answer 1

Answer:

The correct answer is option B, that is, chlorophyll breaks down, exposing other pigment molecules we normally don't see.

Explanation:

Leaves are colored because of the presence of the molecules known as pigments. Chlorophyll is the pigment, which makes the leaves to appear green. Chlorophyll is an essential element for plants as it helps the plant to synthesize food with the help of sunlight.  

At the time of summer and spring, when there is enough amount of sunlight available, the plants produce loads of chlorophyll pigment. However, in autumn when it begins to get cooler, some of the plants stop producing chlorophyll, and those plants dissociate chlorophyll into smaller constituents. With the diminishing of chlorophyll, the other pigments begin to show their colors, and thus, the leaves turn red or yellow at the time of fall.  

Answer 2

The answer would be B.

Chlorophyll breaks down and turns into other pigments such as carotenoids. The chloroplasts transform into chromoplasts where these pigments are stored.

Hope this helps:)