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: C

Rationale: Absent breath sounds on the affected side are a primary symptom of congenital diaphragmatic hernia. Cyanosis, bradycardia, and tachypnea may also be present but are not the primary symptom. Cyanosis is a bluish discoloration of the skin due to poor oxygenation, bradycardia is a slower than normal heart rate, and tachypnea is rapid breathing.

Correct Answer: C

Rationale: Frequent infections can destabilize blood sugar levels, leading to a "brittle" diabetic state in children with type 1 diabetes. Infections increase metabolic demands and can result in significant blood glucose fluctuations, requiring careful monitoring and adjustment of insulin therapy. Noncompliance with diet may affect blood sugar control but is not the primary cause of a "brittle" state. Insulin resistance is more common in type 2 diabetes rather than type 1. Hypothyroidism can impact metabolism but is not directly linked to the development of a "brittle" diabetic state in type 1 diabetes.

Correct Answer: A

Rationale: Handwashing is indeed the most effective way to prevent the spread of hand, foot, and mouth disease in children. Proper hand hygiene helps in removing and killing germs that can cause infections. While isolating sick children and disinfecting toys are important measures to prevent the spread of diseases, they are not as effective as handwashing. Encouraging vaccination, in this case, is not relevant since there is no specific vaccine available for hand, foot, and mouth disease.

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.