Digestion and Absorption

A 38-year-old man from rural Maharashtra presents with chronic diarrhea for 8 months, weight loss of 12 kg, and abdominal bloating after meals. He reports pale, fatty stools that are difficult to flush. On examination, he has mild abdominal distension and glossitis. Laboratory investigations show: hemoglobin 9.2 g/dL, serum albumin 2.8 g/dL, serum calcium 7.1 mg/dL (normal 8.5–10.5), and 72-hour fecal fat 18 g/day (normal <7 g/day). Endoscopy reveals scalloped duodenal mucosa with reduced villous height. Which of the following mechanisms best explains the malabsorption of calcium in this patient?

A 52-year-old woman from Delhi with a 15-year history of type 2 diabetes mellitus presents with postprandial bloating, early satiety, and intermittent diarrhea alternating with constipation. Her fasting blood glucose is 156 mg/dL and HbA1c is 8.9%. Gastric emptying study shows delayed solid food clearance (t½ = 120 minutes; normal <90 minutes). Upper endoscopy is normal. She has no history of gastric surgery. Which of the following best explains the impaired carbohydrate absorption observed in this patient's condition?

Which of the following enzymes is responsible for the initial breakdown of dietary starch in the oral cavity?

Intrinsic factor is essential for the absorption of which vitamin in the terminal ileum?