Tim, a 27-year-old man, has unusually narrow shoulders, low muscle mass, and has no facial and body hair. His doctor recently prescribed testosterone replacement therapy to him. Tim is most likely suffering from:

Correct Answer: C

Rationale: Tim's physical characteristics, such as narrow shoulders, low muscle mass, and lack of facial and body hair, are typical signs of Klinefelter syndrome, a genetic condition where males have an extra X chromosome (XXY). This leads to underdeveloped testes and reduced testosterone production, resulting in features like gynecomastia, sparse facial and body hair, and reduced muscle mass. Testosterone replacement therapy is commonly used to address the hormonal imbalance in individuals with Klinefelter syndrome. Phenylketonuria (PKU) is a metabolic disorder unrelated to the symptoms described in Tim's case. Cystic fibrosis is a genetic respiratory condition that does not present with the physical characteristics mentioned. Huntington's disease (HD) is a neurodegenerative disorder primarily affecting motor function and cognition, not physical appearance and muscle mass.

Correct Answer: B

Rationale: The correct answer is B. Cystic fibrosis is a genetic disorder that causes the body to produce thick, sticky mucus. This mucus can clog the airways in the lungs and obstruct the pancreas, leading to severe respiratory and digestive problems. Choice A is incorrect because uncontrollable muscle movements and personality changes are not typical symptoms of cystic fibrosis. Choice C is incorrect because cystic fibrosis does not directly cause red blood cells to clump together and obstruct small blood vessels. Choice D is incorrect because cystic fibrosis primarily affects the respiratory and digestive systems, not the central nervous system.

Correct Answer: A

Rationale: The correct answer is A: phenotype. A phenotype is the observable characteristics of an individual, which result from the interaction of their genotype with the environment. This interaction between genetics and the environment determines how genes are expressed and how traits are manifested in an individual. Choices B, C, and D are incorrect because chromosomes, alleles, and genotypes are components of an individual's genetic makeup, but they do not directly reflect the observable traits influenced by both genetics and the environment.

Correct Answer: B

Rationale: Applying a cap to the newborn's head is the correct action in this scenario. Newborns are at risk of heat loss due to their high surface area to volume ratio, and maintaining their body temperature is crucial to prevent hypothermia. Giving a warm bath can further increase heat loss and is not recommended. Repositioning the newborn may not address the primary concern of temperature regulation. While monitoring oxygen saturation is important, addressing thermal regulation takes precedence in this situation.

Correct Answer: B

Rationale: The correct answer is B: "Breast milk can be stored in a deep freezer for 12 months." This instruction is important for mothers returning to work to ensure a long-term storage option for breast milk. Choice A is incorrect because thawed breast milk should be used within 24 hours if stored in the refrigerator. Choice C is incorrect as breast milk can be kept at room temperature for only up to 4 hours. Choice D is incorrect as thawed breast milk that is unused should not be refrozen due to safety concerns.