Correct Answer: A

Rationale: The correct answer is A: ileocecal valve. The ileocecal valve is located between the small intestine and the cecum, controlling the passage of chyme. The pyloric valve (choice B) is located between the stomach and the small intestine, regulating the passage of food from the stomach to the small intestine. The cardiac valve (choice C) refers to the valve between the esophagus and the stomach. The hepatic valve (choice D) is not a correct term related to the passage of chyme from the small intestine into the cecum.

Correct Answer: C

Rationale: The correct answer is C - intramural nerve plexus. This network of nerves regulates the muscular movements within the gastrointestinal wall. The gastric nerve plexus (choice A) specifically relates to the stomach, not the entire gastrointestinal tract. The biliary nerve plexus (choice B) is associated with the bile ducts and gallbladder, not the regulation of muscular action. The intestinal nerve plexus (choice D) is a general term that doesn't specifically refer to the network of nerves within the gastrointestinal wall.

Correct Answer: A

Rationale: Glucose serves as a primary source of energy for the body, especially for the brain and muscles. Choice B is incorrect because glucose itself is not responsible for transporting oxygen to cells. Choice C is incorrect as glucose is converted to glycogen, not the other way around. Choice D is incorrect as glucose itself does not play a direct role in maintaining body weight.

Correct Answer: C

Rationale: The correct answer is C: pancreas. Secretin stimulates the pancreas to release bicarbonate, which acts as a buffering solution to neutralize the acid entering the duodenum from the stomach. This process helps in maintaining the pH balance in the small intestine. Choice A, stomach, is incorrect as the stomach does not produce the buffering solution needed for the duodenum. Choice B, liver, is incorrect because secretin does not directly stimulate the liver to produce a buffering solution. Choice D, oxyntic cells, is also incorrect as these cells in the stomach are responsible for producing gastric acid, not the buffering solution needed in the duodenum.

Correct Answer: B

Rationale: The rate at which the stomach empties its contents is primarily determined by the composition of the food consumed. Foods high in fat and protein tend to slow down gastric emptying, while foods high in carbohydrates usually pass through more quickly. Therefore, the composition of food consumed directly impacts the rate of gastric emptying. Choices A, C, and D are incorrect as they do not directly affect the rate of gastric emptying.