Twenty-year-old Jack is extremely tall and has very thick facial hair. Most of his male secondary sex characteristics are also more pronounced than men of his age. In this scenario, Jack is most likely:

Correct Answer: A

Rationale: The correct answer is A: an XYY male. Individuals with XYY syndrome often exhibit increased height and more pronounced secondary male characteristics, such as thick facial hair. Choice B, Klinefelter syndrome (XXY), typically presents with less prominent male secondary sex characteristics due to the presence of an extra X chromosome. Choice C, XXY male, refers to Klinefelter syndrome, which does not align with the description of Jack having more pronounced male secondary sex characteristics. Choice D, Down syndrome, is caused by a trisomy of chromosome 21 and is not associated with the physical characteristics described in the scenario.

Correct Answer: C

Rationale: Sickle cell anemia is most commonly found in individuals of African American descent. This is because sickle cell trait provides some protection against malaria, and historically, regions where malaria is or was prevalent have higher rates of sickle cell anemia. Therefore, individuals with African ancestry are at a higher risk of developing sickle cell anemia compared to other populations. Choices A, B, and D are less likely to develop sickle cell anemia due to lower genetic prevalence in their respective populations.

Correct Answer: B

Rationale: Individuals with cystic fibrosis have a genetic disorder that causes mucus to be thick and sticky, leading to blockages in the lungs and digestive system. This mucus buildup makes them more susceptible to severe respiratory infections, which can ultimately result in premature death in their 20s. Tay-Sachs disease (Choice A) is a genetic disorder that affects the nervous system, not typically causing respiratory infections. Turner syndrome (Choice C) and Klinefelter syndrome (Choice D) are chromosomal disorders that do not directly lead to the respiratory issues observed in cystic fibrosis.

Correct Answer: C

Rationale: The correct answer is C: Midline episiotomy. An episiotomy is a surgical incision made during childbirth to enlarge the vaginal opening. This procedure increases the risk of infection in the postpartum period due to the incision site being a potential entry point for pathogens. Meconium-stained amniotic fluid (choice A) is a risk factor for fetal distress but does not directly increase the mother's risk of infection. Placenta previa (choice B) is a condition where the placenta partially or completely covers the cervix, leading to potential bleeding issues but not necessarily an increased risk of infection. Gestational hypertension (choice D) is a hypertensive disorder that affects some pregnant women but is not directly associated with an increased risk of infection in the postpartum period.

Correct Answer: C

Rationale: During phototherapy using a lamp, it is crucial to protect the newborn's eyes from the light to prevent damage. Closing the newborn's eyes beneath the shield is essential for this purpose. Applying lotion to the skin (Choice A) is not recommended as it can intensify the effects of the phototherapy. Giving glucose water (Choice B) is unrelated to the phototherapy process and is not indicated. Dressing the newborn in clothing (Choice D) may hinder the effectiveness of the phototherapy by blocking the light exposure to the skin.