Correct Answer: C

Rationale: The correct answer is C: 'potassium.' The DASH diet is rich in potassium, which helps lower blood pressure, making it more effective than the typical American diet, which is often low in this essential mineral. Choice A, 'vitamin C,' is incorrect as the comparison is about fiber and another nutrient, not vitamin C. Choice B, 'iron,' is incorrect as the discussion is about fiber and a mineral that helps lower blood pressure, not iron. Choice D, 'sodium,' is incorrect as the DASH diet actually focuses on reducing sodium intake for better blood pressure control, so it wouldn't be a nutrient found in higher amounts compared to the typical American diet.

Correct Answer: B

Rationale: Diabetes mellitus is the correct answer. It is associated with poor wound healing, severe periodontal disease, tissue necrosis, dry mouth (xerostomia), and an increased susceptibility to oral infections like candidiasis. Hypopituitarism, hyperthyroidism, and renal disease are not typically linked to the specific oral manifestations described in the question.

Correct Answer: C

Rationale: The correct answer is C. The bolus is not transported to the stomach by osmosis and gravity, but by peristalsis. Peristalsis is the involuntary constriction and relaxation of muscles to push the bolus through the digestive system. Choices A, B, and D are correct statements. A bolus is indeed a mass of food, the swallowing reflex does move the bolus into the esophagus, and the bolus does not penetrate the diaphragm through the esophageal hiatus; instead, it enters the stomach through the lower esophageal sphincter.

Correct Answer: C

Rationale: Protein deficiency can lead to delayed tooth development as the body may not have enough resources to form teeth properly. This delay can make the teeth more susceptible to dental issues due to incomplete formation. Choices A, B, and D are incorrect. Decreased resistance to dental caries is more related to factors like poor oral hygiene and sugary diets, increased tooth size is not a common effect of protein deficiency on dental tissues, and increased enamel mineralization is not typically associated with protein deficiency.

Correct Answer: B

Rationale: Achalasia is the correct answer. It is a condition characterized by the esophagus having difficulty moving food toward the stomach, resulting in dysphagia (difficulty swallowing). Myasthenia gravis (Choice A) is a neuromuscular disorder that affects skeletal muscles, not the esophagus. Alzheimer's disease (Choice C) primarily affects cognitive function, not the esophagus. Cerebral palsy (Choice D) is a neurological disorder affecting body movement and muscle coordination, unrelated to esophageal dysphagia.