Question

18.many plants have waxy coatings on some surfaces. this coating reduces water loss because it is not water-permeable. this waxy coating is which of the following types of organic molecule?a) proteinb) carbohydratec) nucleic acidd) lipid19.$ce{ch2oh}$ |$ce{o}$ / $ce{ch2oh}$ $ce{oh}$ / $ce{ho}$ |$ce{oh}$what type of monomer is shown?a) monosaccharideb) nucleotidec) glycerold) fatty acid

Explanation:

For question 18: Plant waxy cuticles are hydrophobic (water-repellent) organic molecules, which is a key characteristic of lipids. Proteins, carbohydrates, and nucleic acids are not typically water-impermeable waxy substances.
For question 19: The molecule has a 5-carbon ring structure with multiple hydroxyl (-OH) groups, which is the defining structure of a monosaccharide (the monomer of carbohydrates). Nucleotides contain a nitrogenous base, glycerol is a 3-carbon alcohol, and fatty acids have a long hydrocarbon chain, none of which match the structure shown.

Answer:

1. d) lipid
2. a) Monosaccharide