Correct Answer: C

Rationale: Significant head lag at 8 months is concerning and warrants further evaluation, as it may indicate developmental delays or neurological issues.

Correct Answer: B

Rationale: The correct answer is B: Lack of surfactant. Respiratory distress syndrome (RDS) in preterm infants is primarily due to a lack of surfactant, which is crucial for keeping the lungs inflated. Without adequate surfactant, the alveoli collapse, leading to breathing difficulties. Choice A, Excessive surfactant, is incorrect as RDS is caused by an insufficient amount of surfactant. Choice C, Immature immune system, and Choice D, Lack of body fat, are not directly related to the development of respiratory distress syndrome in preterm infants.

Correct Answer: C

Rationale: In extremely low-birth-weight (ELBW) infants, a thorough systemic physical assessment is crucial to detect subtle changes that may indicate an underlying problem. These infants are highly vulnerable and may show signs of stress through changes in feeding behavior, activity, color, oxygen saturation, or vital signs. Monitoring weight in ELBW infants primarily reflects genitourinary function rather than fluid retention. Difficulties in maternal-child attachment are important but are usually assessed during parental visits and are not the primary focus of a systemic physical assessment. Changes in the Apgar score are used immediately after birth to assess the transition to extrauterine life and are not as relevant in the following 24 hours to detect ongoing subtle issues.

Correct Answer: A

Rationale: The correct answer is A, 'Having imaginary playmates.' Preschool-age children often engage in imaginative play, which includes creating imaginary friends or playmates. This type of play helps them develop creativity, social skills, and emotional expression. Choice B, 'Selective collection of objects,' may be more common in older children and is not a typical play activity for preschoolers. Choice C, 'Complex board games,' are usually beyond the developmental level of preschoolers as they require more advanced cognitive skills. Choice D, 'Associative play,' is a term used to describe a type of play where children play alongside each other but not necessarily together, which is different from the imaginative play involving imaginary playmates that preschoolers often engage in.

Correct Answer: A

Rationale: Vesicular breath sounds are normally heard over most of the lung fields, except near the trachea and main bronchi, where bronchial or bronchovesicular sounds may be heard.