An Rh-negative woman married to a heterozygous Rh-positive man has three children. The probability that all three of their children are Rh-positive is

Correct Answer: C

Rationale: Certainly! The Rh factor follows Mendelian inheritance. The Rh-negative woman is homozygous Rh-negative (rr) and the Rh-positive man is heterozygous (Rr). The Punnett square for their offspring shows a 1/2 chance of each child being Rh-positive (Rr). Therefore, the probability of all three children being Rh-positive is (1/2)^3 = 1/8, making choice C the correct answer. Choices A, B, and D are incorrect because they do not consider the specific genetic inheritance pattern of the Rh factor in this scenario.

Correct Answer: B

Rationale: The correct answer is B: a disturbance in homeostasis. When a human system fails to function properly, homeostasis, the body's ability to maintain internal stability, is disrupted. This can lead to various health issues as the body struggles to maintain balance. Choices A, C, and D do not directly address the concept of homeostasis or the consequences of system failure, making them incorrect. Choice A (a stable rate of metabolism) does not reflect the impact of system failure on homeostasis. Choice C (a change in the method of cellular respiration) is too specific and does not encompass the broader consequences of system failure. Choice D (a change in the function of DNA) is not directly related to the immediate effects of system failure on the body's internal stability.

Correct Answer: B

Rationale: The correct answer is B because pneumocystis jiroveci pneumonia (PCP) results from an impaired immune system. The organism causing PCP exists as part of the normal flora of the lungs but becomes an aggressive pathogen when the immune system is compromised. This is why PCP is commonly seen in individuals with HIV/AIDS or other conditions that weaken the immune system. Choice A is incorrect because PCP is not contracted from pets or through toxoplasmosis transmitted via cat feces. Choice C is incorrect because PCP is not spread through airborne droplets but rather through the inhalation of the fungus. Choice D is incorrect because PCP does not require direct blood contact for transmission; it is primarily contracted through the inhalation of the fungus.

Correct Answer: B

Rationale: Correct Answer: B Rationale: 1. Systemic scleroderma is a connective tissue disease characterized by skin tightening, affecting blood vessels and internal organs. 2. Skin tightening in systemic scleroderma can lead to contractures if not managed with exercises. 3. Nurse must expect skin changes and educate on the importance of range-of-motion and muscle-strengthening exercises. 4. Increased joint flexibility (Choice C) is not expected in systemic scleroderma due to skin and tissue tightening. 5. Excessive salivation (Choice A) and frequent nosebleeds (Choice D) are not typical manifestations of systemic scleroderma.

Correct Answer: B

Rationale: The correct answer is B because washing genitalia using an antimicrobial soap helps prevent the spread of infection in individuals with AIDS. Antimicrobial soaps can kill germs and reduce the risk of transmitting infections. This step is crucial for maintaining personal hygiene and preventing the transmission of pathogens. Rinsing dishes with cold water (Option A) is incorrect because hot and sudsy water is necessary to effectively clean dishes and eliminate germs. Avoiding hand washing (Option C) is incorrect as hand washing is essential for preventing the spread of infections. Using only paper towels to dry hands (Option D) is not as important as proper hand washing with soap and water.