What type of immunity is species-specific, decreasing the chance that a disease will spread from animals to humans?

Choice A reason: Taking pain medications manages symptoms of a sickling crisis but does not prevent it. Sickle cell crises occur due to hemoglobin S polymerization, triggered by hypoxia or dehydration, not directly prevented by analgesics, making this choice incorrect for prevention.

Choice B reason: Avoiding high altitudes reduces hypoxia, a trigger for sickling crises, as low oxygen levels promote hemoglobin S polymerization. While helpful, dehydration is a more significant and common trigger, making this choice less critical than avoiding dehydration.

Choice C reason: A high-protein, high-fat diet does not directly prevent sickling crises. Nutritional balance supports overall health, but sickle cell crises are triggered by dehydration, hypoxia, or infection, not dietary composition, making this choice incorrect for crisis prevention.

Choice D reason: Avoiding dehydration is critical in sickle cell anemia, as low fluid levels increase blood viscosity, promoting hemoglobin S polymerization and red cell sickling. This triggers vaso-occlusive crises, so maintaining hydration prevents these events, making this the correct choice.

Choice A reason: A metabolic deficit of dystrophin causing muscle cell necrosis describes muscular dystrophy, not osteoarthritis. Osteoarthritis involves joint cartilage degradation, not muscle pathology. Dystrophin deficiency affects muscle fiber integrity, unrelated to the joint-specific degenerative process of osteoarthritis, making this choice incorrect.

Choice B reason: Bone infection, or osteomyelitis, is caused by bacteria or fungi, leading to bone destruction. Osteoarthritis is a non-infectious degenerative condition affecting cartilage and subchondral bone due to mechanical stress and aging, not infection, making this choice incorrect for osteoarthritis’s pathophysiology.

Choice C reason: Loss of bone matrix causing fragile bones describes osteoporosis, not osteoarthritis. Osteoarthritis primarily involves cartilage breakdown and joint inflammation, with secondary bone changes like osteophytes, not systemic bone density loss, making this choice incorrect for the joint-focused pathology.

Choice D reason: Osteoarthritis is a degenerative joint disease characterized by progressive cartilage loss due to mechanical stress, inflammation, and aging. This leads to joint pain, stiffness, and bone remodeling, such as osteophyte formation, accurately describing the pathophysiology and making this the correct choice.