Correct Answer: C

Rationale: Daisy's symptoms of short stature and infertility, along with the prescription of estrogen replacement therapy, are indicative of Turner syndrome. Turner syndrome is a genetic condition in which a female is partially or completely missing one X chromosome. This results in short stature, infertility, and other physical characteristics. Phenylketonuria (PKU) is a metabolic disorder caused by a mutation in the gene responsible for the breakdown of the amino acid phenylalanine. Cystic fibrosis is a genetic disorder affecting the respiratory and digestive systems. Huntington's disease (HD) is a neurodegenerative disorder that affects muscle coordination and leads to cognitive decline.

Correct Answer: D

Rationale: Rh incompatibility occurs when the mother's antibodies attack the fetus's red blood cells, leading to serious complications, usually in subsequent pregnancies. Choice A is incorrect because Rh incompatibility often occurs in subsequent pregnancies, not necessarily the first one. Choice B is incorrect as Rh incompatibility does not render a woman infertile but can lead to complications during pregnancies. Choice C is incorrect as Rh incompatibility is not carried by a sex chromosome but involves the Rh factor on red blood cells.

Correct Answer: D

Rationale: Hegar's sign, which is a softening of the lower uterine segment, is considered a probable sign of pregnancy as it indicates changes in the cervix and uterus that occur during pregnancy. Amenorrhea, the absence of menstruation, is a common early sign of pregnancy but can also be due to other factors. Morning sickness, nausea and vomiting, can be a sign of early pregnancy but is not as specific as Hegar's sign. Breast tenderness is a common symptom in early pregnancy due to hormonal changes, but it is not as definitive as Hegar's sign in indicating pregnancy.

Correct Answer: A

Rationale: A primiparous woman who has recently migrated to the US with her spouse is at the highest risk for psychological difficulties during the postpartum period. Recent migration and adjustment to a new environment can increase the risk of postpartum depression, especially when combined with the challenges of being a new mother. Choice B, a multiparous client living with her husband and his family, may have social support from family members, which can be protective against psychological difficulties. Choice C, a multiparous female with a large family living in a community, also indicates potential social support. Choice D, a primiparous adolescent living at home with her parents and significant other, may have a support system in place with her family and significant other.

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.