Trypsinogen when activated by ______ will break down proteins in the ______.

Correct Answer: D

Rationale: The correct answer is D: enterokinase; small intestine. Enterokinase is an enzyme that activates trypsinogen into trypsin in the small intestine. Trypsin is then responsible for breaking down proteins in the small intestine. Enterokinase is not found in the pancreatic ducts, eliminating choices A and C. Trypsinogen is not activated by itself, so choice B is incorrect. In summary, enterokinase activates trypsinogen into trypsin in the small intestine, allowing for protein digestion.

Correct Answer: D

Rationale: The correct answer is D because butyric acid, a short-chain fatty acid formed during colonic fiber fermentation, has been shown to stimulate antioxidant defenses in the colon. This helps protect against oxidative damage, a key factor in the development of cancer. Choice A is incorrect because propionic acid does not inhibit liver fatty acid synthesis in relation to colon cancer. Choice B is incorrect because butyric acid does not silence the SLC5A8 tumor suppressor gene; in fact, it has been shown to have anti-tumor effects. Choice C is incorrect as there is evidence supporting the protective effect of dietary fiber through butyric acid's stimulation of antioxidant defenses.

Correct Answer: C

Rationale: Rationale: C: Complement is produced by glial cells in the brain. This is true as glial cells secrete complement proteins to modulate immune responses in the brain. A: Complement is not released in an activated state but requires activation. B: Complement is activated by foreign molecules, not native proteins in the blood. D: Complement is part of the innate immune response, not just the adaptive immune response.

Correct Answer: A

Rationale: Step 1: Arterioles are smaller branches of arteries that lead to capillaries. Step 2: Arterioles are indeed less muscular than arteries but more muscular than capillaries. Step 3: Arterioles play a crucial role in regulating blood pressure through vasoconstriction and vasodilation. Step 4: Choice A is correct as it accurately describes arterioles' role in blood pressure regulation. Summary: Choice B is incorrect as arterioles are not the most muscular of major vessels. Choice C is incorrect as arterioles have significant innervation. Choice D is incorrect as arterioles do have smooth muscle and connective tissue, and they regulate blood flow efficiently.