Question: Why Do Leaves Change Color in the Fall? Why do they go from green to red/orange? Is it anything to do with the oxygen/carbon dioxide levels?

Daren Fearon answered on 18 Jun 2014:

Leaves are green as they contain a molecule called chlorophyll which is involved in photosynthesis – it helps turn sun light into energy that the plant can use. In winter there is less sun to carry out photosynthesis so the plants survive off the energy stores it has created during summer. As the plant isn’t carrying out photosynthesis, it stops producing chlorophyll and so the green colour fades until it starts getting sunny again and the plants start reproducing chlorophyll and photosynthesis can continue.