An Olympic marathon runner skipped her breakfast on the day of her big run. During her run, his breathing felt normal, but her legs began to cramp up causing her to lose the big race. Which was most likely the limiting factor for the cellular respiration happening in her muscle cells during the race? a. Glucose

b. Carbon dioxide

c. Water

d. Oxygen

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