Correct Answer: A

Rationale: The correct answer is A. Cimetidine (Tagamet) is an H2 receptor antagonist that works by reducing gastric acid secretion. This action helps to decrease the acidity in the stomach, which in turn reduces the symptoms of gastroesophageal reflux. Choice B is incorrect because cimetidine does not neutralize acid but rather decreases its production. Choice C is incorrect as cimetidine does not affect the rate of gastric emptying time. Choice D is incorrect as cimetidine does not coat the lining of the stomach and esophagus but instead works to reduce gastric acid secretion.

Correct Answer: B

Rationale: Rectal bleeding is more commonly associated with ulcerative colitis (UC) than with Crohn disease (CD). While both conditions can cause abdominal pain and growth issues, bleeding is a hallmark of UC due to its superficial mucosal inflammation. Perianal lesions are more characteristic of CD, and growth retardation is typically not a direct clinical manifestation of either CD or UC.

Correct Answer: A

Rationale: The correct answer is A: Breast development (thelarche) is usually the first sign of puberty in females, typically beginning between ages 8 and 13. This marks the start of puberty, followed by pubic hair growth, a growth spurt, and eventually menarche (the onset of menstruation). Pubic hair growth and axillary hair growth usually follow breast development in the sequence of pubertal changes. Therefore, the first noticeable change indicating the onset of puberty in females is the development of breast buds.

Correct Answer: C

Rationale: Croup is the correct answer. It is characterized by a distinctive "barking" cough, typically worse at night, caused by the inflammation of the upper airway, specifically the larynx and trachea. Asthma (Choice A) typically presents with wheezing and shortness of breath rather than a barking cough. Bronchiolitis (Choice B) commonly causes wheezing and respiratory distress in infants and young children. Pneumonia (Choice D) often presents with symptoms like fever, productive cough, and chest pain, but not typically a barking cough.

Correct Answer: D

Rationale: The correct answer is D: Colicky, cramping abdominal pain around the umbilicus. This type of pain is a common early sign of acute appendicitis. Rebound tenderness, choice A, is a later sign seen in the physical examination of a patient with appendicitis. Rectal bleeding, as described in choice B, is not typically associated with appendicitis. Abdominal pain that is relieved by eating, as mentioned in choice C, is more indicative of peptic ulcer disease rather than appendicitis.