Answer:
Hey!
When the Chlorophyll breaks down, the leaves LOSE ITS GREEN COLOUR...this is then seen physically as when the leaves change colour in the Autumn...(red,,,yellow...orange etc)
Step-by-step explanation:
This happens for so many reasons : *here's a couple*
LACK OF SUNLIGHT (reduced daytimes)
TEMPERATURE (as the temperature reduces, Photosynthesis processes slow down, so there's no need for excess Chlorophyll)
HOPE THIS HELPS!!