Correct Answer: B

Rationale: The correct answer is B because while the exact causes of depression in children are not fully understood, research indicates that children are more likely to experience depression if their parents have a major affective disorder. Choice A is incorrect because it suggests that the causes of major depression are entirely unknown, which is not accurate. Choice C is incorrect as there is no conclusive evidence that boys are more likely than girls to be depressed. Choice D is incorrect as the prevalence rate of depression is not necessarily higher in prepubescent children specifically.

Correct Answer: C

Rationale: The correct answer is C: Heart defects. Many children with Down syndrome are born with congenital heart defects. These heart abnormalities are more prevalent in individuals with Down syndrome than in the general population. Choices A, B, and D are incorrect because while they may be congenital defects in children, they are not commonly associated with Down syndrome. Hypospadias is a urogenital condition, pyloric stenosis affects the stomach, and hip dysplasia involves the hip joint, but these are not typically seen as frequently as heart defects in children with Down syndrome.

Correct Answer: C

Rationale: The correct answer is C: Performing self-care activities. For a 5-year-old child diagnosed with cognitive impairment, it is crucial to focus on teaching them basic self-care skills. This includes activities like dressing themselves, feeding, and personal hygiene. These skills are fundamental for their daily living and independence. Choices A, B, and D are not appropriate for a young child with cognitive impairment. Acquiring job skills is not developmentally suitable at this age, making decisions may be challenging due to cognitive limitations, and reading and doing simple math may be too advanced for their current cognitive abilities.

Correct Answer: B

Rationale: In clients with COPD, oxygen therapy can lead to a decrease in the respiratory drive caused by the removal of the hypoxic drive. This can result in carbon dioxide retention, leading to a decreased level of consciousness. Options A, C, and D are incorrect because an increased respiratory rate is typically a sign of hypoxia, improved oxygen saturation is a positive response to oxygen therapy, and complaints of dry mouth are not directly related to oxygen therapy complications in this scenario.

Correct Answer: B

Rationale: The correct answer is B: Activated partial thromboplastin time (aPTT). This test is used to monitor the effectiveness of heparin therapy. A complete blood count (CBC) (choice A) is not specific for monitoring heparin therapy. Prothrombin time (PT) (choice C) and International normalized ratio (INR) (choice D) are more commonly used to monitor warfarin therapy, not heparin.