Final answer:
The flaw in the student's reasoning is the assumption that correlation implies causation, meaning that just because Alzheimer's is prevalent in nursing homes, it doesn't mean living in one causes the disease. Alzheimer's has biological and genetic factors at play that are more likely the cause.
Step-by-step explanation:
The argument that living in a nursing home causes Alzheimer's dementia is flawed because it confuses correlation with causation. The high prevalence of Alzheimer's among nursing home residents could be due to the fact that individuals with Alzheimer's require the kind of care that nursing homes provide, rather than the environment of the nursing homes causing the disease. Furthermore, the elderly population, which is more likely to reside in nursing homes, also has a higher risk of developing Alzheimer's due to age-related factors. Alzheimer's disease is primarily caused by complex biological processes involving amyloid plaques, neurofibrillary tangles, and loss of neurons in areas such as the hippocampus, as well as potential genetic components, rather than solely by environmental factors such as living situations.