The reason the leaves of many trees turn orange and yellow in the fall is:
- frost causes chlorophyll to change color (wrong)
- chlorophyll and carotenoid pigments react with each other to form new colors (wrong)
- plants do not produce chlorophyll in cool weather so it no longer masks carotenoid pigments (correct)
- the chlorophyll pigments are converted to carotenoids (wrong)
- more chlorophyll is produced in the fall (wrong)