Correct Answer: D

Rationale: Polygenic traits, such as height and skin color, are determined by several pairs of genes working together. These traits are influenced by the combined effects of multiple genes across the genome, rather than being controlled by a single gene pair. Choices A, B, and C are incorrect because polygenic traits are not specifically developed during adolescence, transmitted by the mother, or uncommon in humans. Understanding polygenic traits is essential in genetics as they demonstrate the complexity of genetic inheritance and the influence of multiple genes on a single trait.

Correct Answer: A

Rationale: Thalidomide was initially marketed as a treatment for insomnia and nausea, particularly in pregnant women. However, it was later found to cause severe birth defects, leading to significant consequences. Choice B, infertility and impotence, is incorrect as thalidomide was not marketed for these conditions. Choices C and D, Down syndrome and Turner syndrome, are genetic conditions and not conditions for which thalidomide was intended as a treatment.

Correct Answer: A

Rationale: Feeling a tugging sensation while the baby is sucking indicates an effective latch and milk transfer during breastfeeding. This sensation means that the baby is effectively drawing milk from the breast. Choice B is incorrect because infants should ideally have six to eight wet diapers in a 24-hour period to show adequate hydration. Choice C is incorrect as a dark and concentrated urine may indicate dehydration, which is not a sign of effective breastfeeding. Choice D is incorrect as the breast should soften after the baby breastfeeds, indicating that the baby has effectively emptied the breast of milk.

Correct Answer: D

Rationale: Matt is exhibiting symptoms typical of Huntington's disease (HD), a hereditary condition characterized by involuntary movements, cognitive impairment, and behavioral changes. The fact that Matt's father and grandfather had similar issues supports the genetic nature of the disease. Phenylketonuria (PKU) is a metabolic disorder that affects amino acid metabolism, not presenting with the symptoms described. Cystic fibrosis primarily affects the respiratory and digestive systems, not causing the neurological symptoms described. Turner syndrome is a genetic condition affecting females and is not associated with the symptoms described in the case of Matt.

Correct Answer: D

Rationale: On the first postpartum day, the nurse is most likely to find the breasts filling and secreting colostrum. Colostrum secretion is common as the body prepares for breastfeeding in the initial days after delivery. Choice A is incorrect as breasts are not typically very tender immediately postpartum. Choice B is incorrect as an immediate let-down response is more related to lactation rather than the first postpartum day. Choice C is incorrect as the breasts typically undergo changes, such as filling with colostrum, after delivery.