Correct Answer: A

Rationale: An estimated blood loss (EBL) of 1500 ml following a vaginal birth is significant and can lead to hypovolemia. The vital signs provided in option A (Temperature 37.9°C, heart rate 120 bpm, respirations 20 breaths per minute, and blood pressure 90/50 mm Hg) indicate tachycardia and hypotension, which are concerning signs of hypovolemia due to excessive blood loss. Tachycardia is the body's compensatory mechanism to maintain cardiac output in response to decreased blood volume, and hypotension indicates inadequate perfusion. Options B, C, and D do not exhibit the same level of concern for hypovolemia. Option B shows tachypnea, which can be a result of pain or anxiety postpartum. Option C and D have vital signs within normal limits, which are not indicative of the body's response to significant blood loss.

Correct Answer: A

Rationale: The correct answer is A: TRUE. Advanced parental age, particularly maternal age, is associated with an increased risk of Down's syndrome in offspring. As parents get older, the likelihood of having a child with Down's syndrome increases. Choices B, C, and D are incorrect because the risk of Down's syndrome is known to rise with parental age, especially maternal age, due to the increased likelihood of chromosomal abnormalities during egg formation.

Correct Answer: C

Rationale: The correct answer is C: 'Gravida 4, para 2.' Gravida refers to the total number of pregnancies, including the current one. In this case, the client has been pregnant a total of 4 times, so gravida is 4. Para is the number of pregnancies that have reached viability, which is 2 in this case. The client has had a term birth and a set of twins who died within 24 hours, totaling 2 pregnancies that reached viability. Choices A, B, and D are incorrect because they do not accurately reflect the client's obstetric history based on the information provided.

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.

Correct Answer: A

Rationale: To ensure adequate installation of the ophthalmic erythromycin 5% ointment in a newborn, the nurse should instill a thin ribbon into each lower conjunctival sac. This method helps to ensure proper distribution and effectiveness of the medication to prevent neonatal conjunctivitis. Choices B, C, and D are incorrect. Occluding the inner canthus after retracting the eyelids, mummy wrapping the infant, or stabilizing the instilling hand on the neonate's head are not appropriate actions for ensuring the proper installation of the ointment.