Is the freshwater eel a flatworm or an annelid

The rate at which molecules water and oxygen can enter a cell is determined by the-

What re the two main phrases of the cell cycle.

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.