Correct Answer: B

Rationale: Nasal congestion is a common early sign of RSV in infants, often accompanied by cough and wheezing. High fever, rash, and jaundice are not typically associated with RSV. While RSV can lead to fever, it is usually not one of the earliest signs. Rash and jaundice are unrelated to RSV symptoms.

Correct Answer: B

Rationale: Daily chest physiotherapy is crucial in managing cystic fibrosis as it helps clear mucus from the lungs, improves respiratory function, and reduces the risk of lung infections. High-sugar diets are not recommended for individuals with cystic fibrosis as they can contribute to mucus production, exacerbating respiratory issues. Frequent use of antacids is not a primary treatment for cystic fibrosis, as it does not address the underlying lung issues. Limiting fluid intake is not typically advised for individuals with cystic fibrosis, as adequate hydration is essential for maintaining lung function and thinning mucus secretions.

Correct Answer: B

Rationale: Limited range of motion in the hip, often noted as a limitation in abduction, is a common sign of congenital hip dysplasia. This limitation is due to the abnormal development of the hip joint, affecting its movement. Symmetrical hip movement (Choice A) is not a characteristic sign of congenital hip dysplasia. Swelling of the knees (Choice C) is not typically associated with this condition. Dislocated patella (Choice D) refers to a different anatomical structure and is not a common sign of congenital hip dysplasia.

Correct Answer: B

Rationale: Randomization is crucial in a scientific experiment to eliminate bias in the assignment of subjects to groups. By randomly assigning subjects, it helps ensure that any differences observed in the outcomes are due to the experimental treatment and not to preexisting differences between groups. Choice A is incorrect because randomization does not guarantee representativeness but rather minimizes the impact of confounding variables. Choice C is not entirely accurate; while randomization can contribute to accuracy and validity, its primary purpose is to reduce bias. Choice D is incorrect as the goal of randomization is not to balance the number of subjects but to prevent systematic differences between groups.

Correct Answer: B

Rationale: In a child with congenital adrenal hyperplasia (CAH), monitoring electrolyte balance is crucial. CAH can lead to adrenal insufficiency, causing imbalances in electrolytes such as sodium and potassium. Monitoring electrolyte levels helps in preventing complications like dehydration, electrolyte disturbances, and adrenal crisis. While blood glucose levels may need monitoring in other conditions like diabetes, it is not the primary concern in CAH. Urine output is important in assessing kidney function but is not a direct monitoring parameter for CAH. Hemoglobin levels are more relevant in conditions such as anemia, not specifically in CAH.