Correct Answer: B

Rationale: The correct site to administer an intramuscular (IM) vaccine to a newborn is the vastus lateralis muscle. For newborns, the vastus lateralis is preferred over the dorsogluteal site because the dorsogluteal site has been associated with low antibody seroconversion rates, indicating a reduced immune response. The vastus lateralis is also recommended for IM injections in newborns, while the deltoid muscle is preferred for older infants and children. The ventral gluteal muscle and the biceps muscle are not appropriate sites for IM injections. Therefore, choice B is the correct answer.

Correct Answer: D

Rationale: Oral sucrose and nonnutritive sucking are effective nonpharmacologic interventions for reducing procedural pain in neonates.

Correct Answer: A

Rationale: The Snellen letter chart is the most commonly used test for measuring visual acuity, particularly in school-age children and adults.

Correct Answer: A

Rationale: The correct answer is A: Respiratory syncytial virus (RSV). RSV is the most common cause of bronchiolitis, especially in infants. Bronchiolitis is characterized by inflammation of the small airways in the lungs. Choice B, Haemophilus influenzae, is a bacterium that can cause respiratory infections but is not the primary cause of bronchiolitis. Choice C, Parainfluenza, is a common viral infection that can cause croup and other respiratory illnesses but is not the main cause of bronchiolitis. Choice D, Rotavirus, is a virus that primarily affects the gastrointestinal system, causing diarrhea and vomiting, and is not associated with bronchiolitis.

Correct Answer: B

Rationale: Allowing adolescents to express their feelings helps them feel heard and supported, which is crucial for effective communication.