Correct Answer: A

Rationale: Tay-Sachs disease is a genetic disorder that causes a progressive degeneration of the central nervous system, particularly in infants. Choice B, Cystic fibrosis, is a genetic disorder that primarily affects the lungs and digestive system, not the central nervous system. Choices C and D, Turner syndrome and Klinefelter syndrome, are chromosomal disorders that do not directly involve degeneration of the central nervous system.

Correct Answer: C

Rationale: The correct intervention in this scenario is to administer ampicillin 2 grams intravenously. This is crucial to prevent Group B Streptococcus infection in the newborn during delivery. Option A, transfusing packed red blood cells, is not indicated based on the hemoglobin and hematocrit levels provided. Option B, giving measles, mumps, rubella vaccine, is not necessary at this time. Option D, injecting hepatitis B immune globulin, is not appropriate for the conditions presented in the question.

Correct Answer: D

Rationale: After an amniocentesis, the nurse should monitor the client for potential complications, with hemorrhage being a significant concern due to the invasive nature of the procedure. Hyperemesis (severe vomiting), proteinuria (excessive protein in the urine), and hypoxia (low oxygen levels) are not typically associated with amniocentesis and are less likely to occur compared to hemorrhage, which is a more common complication that requires prompt recognition and intervention.

Correct Answer: D

Rationale: During the transitional phase of labor, which is the most intense phase, the primary focus of nursing care for a client who anticipates an unmedicated delivery should be assisting her to maintain control. This is essential to help her manage the intense pain and anxiety associated with this phase without the use of medication. Assessing the strength of uterine contractions (Choice A) is important but not the primary focus during the transitional phase. Re-evaluating the need for medication (Choice B) is not applicable as the client anticipates an unmedicated delivery. Reminding her to push 3 times with each contraction (Choice C) is more related to the pushing stage of labor and not the transitional phase.

Correct Answer: B

Rationale: The correct answer is B: Adenine. In the structure of DNA, adenine pairs with thymine through hydrogen bonding, forming one of the complementary base pairs that make up the double helix structure of DNA. Cytosine pairs with guanine, not thymine. Rhodamine and serine are not DNA bases and do not participate in DNA base pairing. Therefore, choices A, C, and D are incorrect.