Which of the following is true regarding soil? Soil is an ecosystem because it contains many interacting biotic and abiotic components. Soil consists only of biotic components, so it is not an ecosystem. Soil consists only of abiotic components, so it is not an ecosystem. Soil is just "dirt" and would not be considered an ecosystem.

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