Q1. Animals obtain energy throughout a series of chemicals reactions in which sugar (C6 H12 O6) and oxygen gas (O2) are reactant. This produces water (H2O) and carbon dioxide (CO2) as waste products. How might you use a radioactive isotope to find out whether the oxygen in CO2 comes from sugar or oxygen gas?

Q2. Suppose that a mad scientist invents a death-ray that destroys a person’s ciliary, sphenopalatine, and submandibular ganglia (and nothing else). Examine all the symptoms the victim would show. Would the victim die, or would scientist have to go back to the laboratory to invent a more effective death-ray?