Final answer:
Scrapie is not a human disease caused by prions but a prion disease that affects sheep and goats. Diseases like kuru, fatal familial insomnia, and Creutzfeldt-Jakob disease are human prion diseases.
Step-by-step explanation:
The answer to the student's question about which disease is not caused by prions is D) Scrapie. Scrapie is a prion disease that affects sheep and goats, not humans. Human diseases caused by prions include kuru, fatal familial insomnia, Gerstmann-Straussler-Scheinker disease, and Creutzfeldt-Jakob disease (CJD). These diseases are all classified as transmissible spongiform encephalopathies (TSEs), which are fatal neurodegenerative diseases. Prions do not contain nucleic acids such as DNA or RNA and are composed solely of a type of abnormal protein that can infect and replicate within the host.