The major part of the aqueous component (other than water) of pancreatic juice is

Correct Answer: C

Rationale: The correct answer is C: bicarbonate ions. Pancreatic juice is alkaline to neutralize the acidic chyme entering the small intestine from the stomach. Bicarbonate ions are secreted by pancreatic duct cells and play a major role in maintaining the pH balance. Mucus (choice A) is produced by goblet cells and helps protect the lining of the digestive tract but is not a major component of pancreatic juice. Trypsinogen, chymotrypsinogen, and procarboxypeptidase (choice B) are pancreatic enzymes, not the major component of the aqueous component. Secretin (choice D) is a hormone that stimulates the pancreas to release bicarbonate ions but is not a component of pancreatic juice itself.

Correct Answer: B

Rationale: The correct answer is B because the colonic microbiota performs multiple essential functions such as aiding in digestion, producing vitamins, regulating immune function, and maintaining gut barrier integrity. Option A is incorrect as it focuses on dietary fiber intake rather than the microbiota's functions. Option C is incorrect because while acetate, propionate, and butyrate are important organic acids produced, they are not the only ones. Option D is incorrect as the microbiota's establishment of an 'acetate buffer' does not necessarily suppress the growth of all pathogenic bacteria.

Correct Answer: D

Rationale: The correct answer is D because the hypothalamus acts as the body's thermostat and controls temperature regulation. When the body detects an infection or other triggers, the hypothalamus resets the temperature set point higher, causing a fever response to help fight off the infection. Choices A, B, and C are incorrect because while an infection can trigger a fever response, it is the hypothalamus that ultimately controls and initiates the response by resetting the temperature set point, not a local widening of blood vessels or activation of the complement system.

Correct Answer: B

Rationale: The correct answer is B: Resveratrol can mimic the effects of caloric restriction in worms, yeast, and flies. This is true because resveratrol, a compound found in red wine, has been shown to activate certain proteins and enzymes that are also activated during caloric restriction, leading to improved health and longevity in these organisms. A is incorrect because caloric restriction typically leads to decreased insulin signaling, not stimulation. C is incorrect because while CR has been shown to increase lifespan in various animal models, there is limited evidence to support its effects on human lifespan. D is incorrect because not all statements are true - only B is supported by scientific evidence.

Correct Answer: A

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.