Final answer:
The term 'endable' in the context of medical conditions, such as those caused by prions, refers to diseases that are incurable and ultimately fatal. Currently, there are no treatments available for prion diseases, but research is ongoing to develop potential therapies.
Step-by-step explanation:
When a medical condition, such as an infectious disease caused by prions, is referred to as endable, it implies that the condition is incurable and cannot be halted in its progression. Prion diseases are currently not treatable and are considered inevitably fatal. Options such as treatable but not curable, terminal, and non-treatable are not accurate descriptors for being endable. Being endable specifically refers to conditions that cannot be cured. However, healthcare professionals and researchers strive to provide ongoing support, and scientists continue to search for treatments or potential cures for prion-related diseases.