Scientists estimate that Earth houses 8.7 million species. All of them use the same cellular fuel: ATP. ATP can be produced via two cellular respiration pathways, one that occurs in the presence of oxygen and one that occurs in its absence. Using your Chapter Readings and reliable sources:

• Name and explain how these two mechanisms differ. Can an organism use both? Support your answer with examples.
• Provide at least two arguments supporting the theory that glycolysis is believed to be the first energy production mechanism on Earth.
• Explain how ethanol biofuel is produced. Provide at least one argument in favor for and one against the use of biofuels.

Your completed journal assignment should be 350 to 450 words. If outside sources are used, include in-text citations and references in your journal submission