Can someone help me, please?
 Organic, Biological, and Nuclear Chemistry.
 17. Which of the following is not an example of a lipid?
 A. Waxes
 B. Fats
 C. Ribose
 D. Oils
 18. _______ is the radioisotope commonly used to map a human's circulatory system.
 A. Iron-59
 B. Carbon-14
 C. Cobalt-60
 D. Technetium-99m