What term is used to describe a group of bacterial cells that is visible to the naked eye?

What is the name for a substance formed in a chemical reaction

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.

The pronunciation aid that determines the stress placed upon a syllable is the