Organs that lie outside the abdominal cavity such as the duodenum, pancreas, urinary bladder and rectum are

Correct Answer: C

Rationale: The correct answer is C: retroperitoneal. Organs like the duodenum, pancreas, urinary bladder, and rectum are considered retroperitoneal because they lie behind the parietal peritoneum, which lines the abdominal cavity. They are not completely covered by visceral peritoneum (B) as they are not suspended in the abdominal cavity. They are not covered by parietal peritoneum (A) as this layer lines the abdominal wall. While these organs are covered with serous membranes (D), the defining characteristic is their location behind the peritoneum, making option C the most accurate choice.

Correct Answer: B

Rationale: The correct answer is B: carbonic acid. Carbonic acid is produced when carbon dioxide reacts with water in the stomach, forming hydrogen ions that combine with chloride ions to create hydrochloric acid. Lactic acid (A), citric acid (C), and acetic acid (D) do not directly contribute to the formation of hydrochloric acid in the stomach. Therefore, they are incorrect choices for this question.

Correct Answer: C

Rationale: The correct answer is C: pancreas. The pancreas is responsible for producing various digestive enzymes such as proteases, lipases, and amylases that aid in breaking down nutrients in the small intestine. These enzymes are released into the small intestine to further digest chyme. The stomach (A) primarily produces gastric juices, not digestive enzymes. The liver (B) produces bile, which helps in fat digestion but is not classified as an enzyme. The small intestine (D) absorbs nutrients but does not produce the majority of digestive enzymes.

Correct Answer: B

Rationale: The correct answer is B: colon. The colon is characterized by having a simple columnar epithelium in its tunica mucosa, smooth muscle in its tunica muscularis, and epiploic appendages attached to its outer surface. The cecum (A) is a pouch-like structure at the beginning of the large intestine. The rectum (C) is the final segment of the large intestine before the anal canal (D). The anal canal is lined by stratified squamous epithelium, not simple columnar epithelium like the colon.

Correct Answer: C

Rationale: The correct answer is C (7-9) because trypsin and chymotrypsin are proteolytic enzymes that function optimally in slightly basic environments. At pH 7-9, these enzymes maintain their structural integrity and catalytic activity. Choices A, B, and D are incorrect because trypsin and chymotrypsin are not acidic enzymes, so pH ranges 1-3 and 10-12 would denature and inactivate them, while pH 5-7 is still on the acidic side, not optimal for these enzymes.