Which best describes the structure of the molecules that make up proteins? A. Carboxyl group + amino group + side chain
B. Carbon + hydrogen + oxygen
C. Phosphate + sugar ring + nucleotide base
D. Hemoglobin + oxygen + iron

Which of the following statements accurately defines epidermis? a. a thick protein fiber composed of the protein collagen b. hard, dense bone tissue found on the outer surface of a bone c. single layer of epithelial cells and the underlying basal lamina d. outer, protective layer of the skin composed of stratified squamous keratinized epithelial tissue