Final answer:
The condition named after a physician named James affecting over 1% of Americans over 65 is Parkinson's Disease, which causes symptoms like tremors and balance issues and was characterized by James Parkinson in the 19th century.
Step-by-step explanation:
The condition named after a physician named James that affects more than 1% of Americans over 65 is Parkinson's Disease. This neurodegenerative disease was first characterized by James Parkinson in 1817 and is not to be confused with Alzheimer's Disease, which was explored by Solomon Carter Fuller and affects one in every eight people age 65 or older. Parkinson's Disease results from the loss of dopamine neurons in the substantia nigra, causing symptoms such as tremors, slowed movement, and balance issues.
While Alzheimer's is more prevalent in the older population, Parkinson's Disease also significantly impacts this age group and involves both motor and sometimes psychological symptoms, including dementia.
The condition affecting more than 1% of Americans over 65 and named for a physician named James is Parkinson's Disease (C on the provided options).