Which of the following best describes prions?

Prions are best described as infectious proteins. They are unique infectious agents composed solely of protein without any nucleic acids (such as DNA or RNA) found in viruses, bacteria, or other pathogens. Prions cause neurodegenerative diseases by inducing abnormal folding of normal brain proteins, which leads to brain damage and characteristic symptoms associated with prion diseases, such as Creutzfeldt-Jakob disease. This distinction as proteins highlights their unique mechanism of pathogenesis compared to other infectious agents.

The other descriptions do not accurately capture what prions are or how they function; they are neither non-pathogenic organisms nor bacterial or viral agents. This delineation is crucial for understanding the nature of prion disease, which relies on protein misfolding rather than traditional infectious pathways involving genetic material.