During a prenatal visit, for which of the following clients should the nurse auscultate the fetal heart rate?

Correct Answer: D

Rationale: The correct answer is D because feeling quickening typically occurs around 18-20 weeks of gestation, indicating fetal movement. This is an appropriate time to auscultate the fetal heart rate. Choice A is incorrect because a molar pregnancy is not a viable pregnancy, and auscultating the fetal heart rate in this case is not applicable. Choice B is incorrect because a crown-rump length of 7 weeks gestation is too early for fetal heart rate auscultation. Choice C is incorrect because a positive urine pregnancy test alone does not indicate the appropriate timing for fetal heart rate auscultation.

Correct Answer: A

Rationale: The typical sex chromosome pattern for females is XX. Females have two X chromosomes, which is represented as XX. Choice B (XYY) is incorrect as it represents the sex chromosome pattern for males with an extra Y chromosome. Choice C (XY) is the sex chromosome pattern for males. Choice D (XXY) represents a genetic disorder known as Klinefelter syndrome, where males have an extra X chromosome.

Correct Answer: C

Rationale: A person is homozygous for a trait when they have two identical alleles for that trait. In this case, both alleles are the same, indicating a homozygous genotype. Choice A, 'monozygous,' is incorrect as it refers to identical twins originating from a single fertilized egg. Choice B, 'dizygous,' is also incorrect as it refers to fraternal twins or individuals that develop from two separate fertilized eggs. Choice D, 'hemizygous,' is incorrect because it describes a genetic condition where only one allele is present in a diploid organism, typically related to genes on the sex chromosomes.

Correct Answer: C

Rationale: Down's syndrome, also known as trisomy 21, is caused by the presence of an extra chromosome on the 21st pair. Choice A is incorrect as alcohol abuse is not the cause of Down's syndrome. Choice B is incorrect because Down's syndrome is not related to sex-linked chromosomal abnormalities. Choice D is also incorrect as drug abuse by the mother during pregnancy is not the cause of Down's syndrome.

Correct Answer: C

Rationale: Individuals with Klinefelter syndrome have an extra X chromosome (XXY) and typically have reduced testosterone levels, which can lead to gynecomastia (enlarged breasts). This condition is not usually associated with Down syndrome (choice A), XYY syndrome (choice B), or Turner syndrome (choice D), making them less likely to have gynecomastia.