Question

why leaves become brown or red colour in winter???​

Answer 1

Answer:

But winter is cold, dry, and usually there isn't much sun (which helps give plants energy). ... Instead, those plants break down chlorophyll into smaller molecules. As chlorophyll goes away, other pigments start to show their colors. This is why leaves turn yellow or red in fall.

Answer 2

Answer:

A substance called chlorophyll colors the leaves green and helps the plant make food. During fall and winter, it is darker and the trees can't make as much food. The chlorophyll is no longer in the leaves and so they start to change color.