Phases of AIDS.

Choice A reason: Active lifestyle and community engagement are protective, not risk factors, for hip fractures. Small frame and age-related bone loss increase fracture risk, so this misidentifies beneficial factors as risks and is incorrect.

Choice B reason: Active lifestyle and social engagement may reduce risk, but the question asks for risk factors. Small frame and age-related bone loss are primary risks for Ms. Major’s fracture, so this is incorrect.

Choice C reason: Healthy diet and social support are protective, not risk factors. Ms. Major’s small frame and age (60) increase bone density loss, elevating fracture risk, so this is incorrect.

Choice D reason: Small frame and age-related bone density loss (at 60) increase Ms. Major’s hip fracture risk, as lower bone mass and aging weaken bones. These are key risk factors, making this correct.

Choice A reason: Polycythemia involves an increased erythrocyte count, not a decrease. A low erythrocyte count causes anemia, leading to fatigue or hypoxia, not the neurological symptoms like headaches or dizziness seen in polycythemia, making this an incorrect cause.

Choice B reason: Tissue destruction by macrophages is not a primary feature of polycythemia. It may occur in inflammatory conditions, but polycythemia’s neurological symptoms stem from blood flow changes, not macrophage activity, making this an incorrect cause.

Choice C reason: Increased blood viscosity, due to elevated red blood cell mass in polycythemia, impairs cerebral blood flow, causing neurological symptoms like headaches, dizziness, and confusion. This sluggish circulation directly affects brain perfusion, making it the primary cause of these symptoms.

Choice D reason: Hypoxia occurs in conditions with inadequate oxygen delivery, like anemia or lung disease. Polycythemia increases oxygen-carrying capacity but causes symptoms due to viscous blood flow, not hypoxia, making this an incorrect primary cause.