Scientists stanley miller and harold urey sealed water, methane, ammonia, and hydrogen in a flask, to simulate earth’s early environment. they exposed the chemicals to electric charges to simulate lighting. what did the process produce? a. nucleic acids b. bacteria c. viruses d. amino acids

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.