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: 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.

Correct Answer: A

Rationale: Chromosomes are rod-shaped structures that carry genetic information in the form of DNA. They are typically seen as elongated structures when visualized under a microscope. Choice B, circular, is incorrect as chromosomes do not have a circular shape; they are linear. Choice C, cone-shaped, is not accurate as chromosomes do not resemble cones in any way. Choice D, octagonal, is also incorrect as chromosomes do not have an octagonal appearance. Therefore, the correct answer is A, rod-shaped, which accurately describes the shape of chromosomes.

Correct Answer: B

Rationale: Misoprostol can be used for induction in clients with gestational diabetes mellitus. Choice A, a client with active genital herpes, is not a candidate for misoprostol induction due to the risk of viral shedding and transmission. Choice C, a client with a previous uterine incision, may be at risk for uterine rupture with misoprostol use. Choice D, a client with placenta previa, is not an appropriate candidate for misoprostol induction due to the risk of increased bleeding associated with the condition.

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.