Herbicides are chemicals that kill plants by interrupting important biological processes. Different herbicides affect different plant processes. The herbicide atrazine prevents the chemical reactions that use energy from sunlight. A plant is sprayed with atrazine.
Exposure to atrazine causes an immediate decrease in the production of two substances in plant. Select the substance.
A. DNA
B. Carbon dioxide
C. Oxygen
D. Phospholipids

oxygen because that's one of the substance that plants produce.

You can also do this by the process of elimination. Knowing that atrazine impedes the production of substances in plants, we know that it can't be DNA and Phospholipid. Carbon Dioxide is used by plant, not produced; thus, oxygen is the answer.

4.) metal

"-the movement of carbon from the nonliving environment into living things and back to the environment

-carbon is the essential component of proteins, fats, and carbohydrates (which make up all organisms)

-carbon exists in air, water, and living organisms

-producers convert carbon dioxide in the atmosphere into carbohydrates during photosynthesis

-bacteria in the atmosphere cycles through the system in filtration units

-in cellular respiration, carbon is released back into the atmosphere as carbon dioxide

-some carbon is stored in limestone (forming one of the largest "carbon sinks" on earth)

-largest carbon reservoir on earth= limestone

-carbon stored in the bodies of organisms as fat, oils, or other molecules may be released into the soil or air when the organism dies

-this may form deposits of coal, oil, or natural gas (fossil fuels, which increased the atmospheric carbon dioxide)

-fossil fuels store carbon left over from bodies of organisms that died millions of years ago

-they are located in the surface of earth, deep within the earth and beneath the ocean floor."    

that is true   : ) hope this you