What term describes an organism capable of causing disease?

The term that describes an organism capable of causing disease is "pathogen." Pathogens include a wide range of disease-causing agents such as bacteria, viruses, fungi, and parasites. Understanding this term is crucial in the field of biomedicine because it encompasses all entities that can lead to infection or disease in a host.

Bacteria and viruses are specific types of pathogens; however, classifying them under the broader category of pathogens highlights their shared ability to cause illnesses. Antibodies, on the other hand, are proteins produced by the immune system to neutralize pathogens, which makes them the body's defense mechanism rather than a disease-causing entity. Therefore, the correct term that captures all organisms capable of causing disease is indeed "pathogen."