Correct Answer: C

Rationale: Most of the chemical digestion occurs in the small intestine. Enzymes in the small intestine break down nutrients into smaller molecules that can be absorbed by the body. The stomach plays a role in digestion by breaking down food mechanically and initiating some chemical digestion, but the majority of nutrient breakdown and absorption happens in the small intestine. The large intestine mainly absorbs water and salts, with little to no digestion taking place there. The esophagus is a muscular tube that helps move food from the mouth to the stomach and does not participate in digestion.

Correct Answer: C

Rationale: Efferent fibers, which carry motor commands, exit the spinal cord through the ventral aspect, also known as the anterior aspect. The correct answer is C, 'Through the ventral aspect.' Efferent fibers exiting through the ventral aspect are responsible for carrying motor commands from the spinal cord to the muscles and glands. Choices A, B, and D are incorrect. Efferent fibers do not exit through the dorsal, lateral, or anterior aspects of the spinal cord.

Correct Answer: A

Rationale: The correct answer is A: Lateral. Lateral refers to a position farther away from the midline of the body. In the example provided, the little toe is indeed lateral to the big toe on the same foot. This is in contrast to 'medial,' which means closer to the midline. 'Proximal' refers to a position closer to the point of attachment or the trunk of the body, while 'distal' refers to a position farther from the point of attachment or the trunk of the body.

Correct Answer: C

Rationale: The purpose of a catalyst is to increase a reaction's rate by decreasing the activation energy required for the reaction to occur. This allows the reaction to proceed more quickly without being consumed in the process. The catalyst provides an alternate mechanism with a lower activation energy, making it easier for the reactants to convert into products. Choice A is incorrect because a catalyst lowers, not increases, the activation energy. Choice B is incorrect because a catalyst does not affect the temperature directly but provides an alternative pathway for the reaction to occur more easily. Choice D is incorrect because a catalyst does not lower the temperature but facilitates the reaction by lowering the activation energy barrier. Therefore, the correct answer is C, 'To increase a reaction rate by decreasing the activation energy.'

Correct Answer: D

Rationale: Potency refers to a cell's potential to differentiate into different cell types. It is not related to the cell's ability to survive (Choice A), move (Choice B), or divide rapidly (Choice C). Stem cells, for example, exhibit varying degrees of potency based on their capacity to give rise to various cell types. Therefore, the correct answer is D as it accurately defines the concept of potency in cells.