1. In winter, plants exchange the saturated lipids in their cell membranes for unsaturated lipids. Unsaturated lipids are "bent" and keep the membranes more fluid, or pliable, because they cannot be stacked closely together. Of what advantage would this change (to an unsaturated lipid) be for green stemmed (herbaceous) plants that live through the winter? (Hint: What happens to bacon grease after it cools or the grease on top of soup when you put it in the refrigerator?)
2. What could the liquid be in the test tube(excluding disaccarides and nucleic acids), if one of the test come up positive?