why the leaves become yellow on Fall?

Answer 1

Because trees like make-overs too!

Answer 2

Leaves get their green color from chlorophyll, a pigment found in plant leaves that enables them to process sunlight. Fall's shorter days and cooler temperatures cause the chlorophyll to move from the leaves to the branches, trunk, and roots, and the yellow and orange pigments that are always present become visible.
Other chemical processes produce the brilliant reds, purples and bronzes. On warm fall days, sugar is produced in the leaves of some trees and then trapped by the chill of night. As sugar accumulates, the leaves turn brighter red.

Answer 3

Chlorophyll (green pigment) is broken down during a hard freeze, but other pigments, like the carotenoids (yellow pigments) are left intact. Thus you see the golden colors of leaves like aspen in the fall.

The other kind of leaf color pigments are called anthocyanins (red pigments).

Answer 4

Because the chlorophyll flows back into the tree in fall.

Answer 5

cuz in the summer the hot and the sun suck the chlorophyle(the substance that make things green) and leave the leaves greenless in other words yellow

Answer 6

The trees require to make different nutrients before they hibernate in the winter. The green leaves make one kind of food, the other color leaves make different.

Answer 7

good morning
seasonal change; death of the old year
the brilliance of fall, hibernation of earth
the elders.....the sign of the times for we in the NE
winter approaches

Answer 8

because they are like fruit-they are ripe!