Correct Answer: B

Rationale: Live vaccines, like the measles, mumps, and rubella (MMR) vaccine, should not be administered to immunosuppressed infants, such as those undergoing chemotherapy. The weakened immune system of these infants may not be able to handle live vaccines safely, potentially leading to severe complications. Therefore, it is crucial to avoid giving live vaccines like MMR to infants receiving chemotherapy. Choice A is incorrect as delaying the MMR vaccine until the infant reaches 2 years of age is not the main concern in this scenario. Choice C is incorrect because although MMR vaccination is important for disease prevention, it should not be given to immunosuppressed infants. Choice D is incorrect as immediate action is needed to prevent potential harm from live vaccines in immunosuppressed infants.

Correct Answer: B

Rationale: A macule is defined as a flat, discolored area on the skin that is different from surrounding tissue due to a change in color. In this case, the baby has a flat, discolored area on the skin, which fits the description of a macule. A papule is a small, raised solid bump, a vesicle is a small fluid-filled blister, and a scale is a flake of skin that is often dry and rough. Therefore, choices A, C, and D do not accurately describe the flat, discolored area on the baby's skin, making them incorrect.

Correct Answer: B

Rationale: The correct answer is B: "Toddlers are learning to assert independence, and this behavior is expected at this age." At 18 months, toddlers are in the stage of developing autonomy and independence. They may exhibit behaviors like temper tantrums and defiance as they assert their independence and test limits. It is crucial for parents and caregivers to understand that these behaviors are typical for toddlers at this age. Choice A is incorrect because discipline should be age-appropriate and focus on positive reinforcement rather than preventing antisocial behaviors. Choice C is inappropriate as leaving a toddler alone in a crib after explaining unacceptable behavior is not a recommended approach and can lead to feelings of abandonment. Choice D is inaccurate as the described behavior is more related to asserting independence rather than the initiative stage of development.

Correct Answer: A

Rationale: The correct answer is A. Surfactant therapy is explained to parents as a treatment that enhances the lungs' ability to exchange oxygen and carbon dioxide. This is essential for premature infants with respiratory distress syndrome (RDS) as it helps improve their respiratory function. Choices B, C, and D are incorrect because surfactant therapy primarily focuses on addressing lung function and is not related to sedation, apnea reduction, or fighting respiratory tract infections.

Correct Answer: D

Rationale: A low-phenylalanine diet is necessary for infants with PKU because it helps prevent the accumulation of phenylalanine, which can result in brain damage. Fat-free (Choice A) and protein-enriched (Choice B) diets are not specifically indicated for PKU. While phenylalanine-free (Choice C) may seem logical, complete elimination of phenylalanine is not practical or safe as it is an essential amino acid. Therefore, the correct choice is a low-phenylalanine diet, which restricts phenylalanine intake to a safe level.