Correct Answer: D

Rationale: During the second stage of labor, the cervix is fully dilated, and the client delivers the newborn. The expulsion of the placenta occurs during the third stage of labor, not the second stage. Regular contractions typically begin in the first stage of labor, not the second. Gradual dilation of the cervix occurs during the first stage of labor, specifically during the active phase.

Correct Answer: D

Rationale: After mitosis, the genetic code is typically preserved and remains identical in the new cells. However, mutations can occur due to radiation or environmental influences, leading to changes in the DNA sequence and potentially altering the genetic code. Therefore, the correct answer is 'mutations.' Choices A, B, and C are incorrect because reductions, expulsions, and conceptions do not accurately describe the changes in the genetic code that can result from external factors. Mutations are the only option that reflects the alteration in the genetic code caused by external influences, making it the correct choice in this context.

Correct Answer: A

Rationale: Monozygotic (MZ) twins share 100% of their genes because they originate from the same fertilized egg that splits into two, resulting in identical genetic material for both twins. Choice B (75%) is incorrect as it implies a partial genetic similarity, which is not the case for MZ twins. Choice C (50%) is incorrect as it suggests half of the genes are shared, which is applicable to dizygotic (DZ) twins, not MZ. Choice D (25%) is incorrect as it indicates minimal genetic sharing, which is not true for MZ twins.

Correct Answer: B

Rationale: In a situation where an infant receives a low Apgar score of 3 following a traumatic delivery, the most crucial intervention for the nurse to implement is to continue resuscitative efforts. A low Apgar score indicates that the newborn is in distress and requires immediate medical attention to support breathing, heart rate, muscle tone, reflex irritability, and color. Continuing resuscitative efforts is essential to provide life-saving interventions promptly. Paging the pediatrician may cause a delay in crucial interventions, repeating the Apgar assessment in 5 minutes is not appropriate as immediate action is needed to stabilize the infant, and informing parents should not take precedence over providing immediate medical care to the newborn.

Correct Answer: B

Rationale: Folic acid deficiency during pregnancy is a well-known risk factor for neural tube defects, including spina bifida occulta, making supplementation critical in prenatal care. Folic acid plays a crucial role in neural tube formation during early pregnancy. Short intervals between pregnancies do not directly impact the development of spina bifida occulta. Preeclampsia is a hypertensive disorder of pregnancy and is not directly linked to spina bifida occulta. While tobacco use during pregnancy has various adverse effects, it is not the primary factor influencing the development of spina bifida occulta in newborns.