Why leaves of touch-me-not closed down on touching

The leaves close under various other stimuli, such as touching, warming, blowing, or shaking. ... The stimulus can also be transmitted to neighboring leaves. It is not known exactly why Mimosa pudica evolved this trait, but many scientists think that the plant uses its ability to shrink as a defense from herbivores

the generally accepted parts of modern cell theory include: all known living things are made up of one or more cells. all living cells arise from pre-existing cells by division. the cell is the fundamental unit of structure and function in all living organisms.