What is the name for an organized group of cells that work togethe?

What would happen to the nutrients in an ecosystem if decomposers, such as bacteria, didn’t exist there?

Why do leaves change color in the fall? green pigments break down and no longer mask the color of chlorophyll. chlorophyll breaks down and no longer masks the colors of other pigments. red- and yellow-colored pigments grow and mask green-colored chlorophyll. green-colored chlorophyll breaks down and turns red and yellow.

Aboy jumps into a cold swimming pool and his body tempature goes down hus muscles ,blood vessels