What term best describes an infectious disease?

The term that best describes an infectious disease is "contagious." This is because infectious diseases are primarily caused by pathogens such as bacteria, viruses, fungi, or parasites that can be transmitted from one individual to another, either directly or indirectly. Contagious diseases are particularly easy to spread, often requiring only close contact with an infected individual or exposure to contaminated surfaces, air, or bodily fluids for transmission to occur.

In contrast, the other terms do not accurately capture the nature of infectious diseases. "Permanent" suggests a condition that lasts indefinitely without improvement or recovery, which does not apply to many infectious diseases that can be resolved with appropriate treatment. "Chronic" refers to diseases that persist over a long time, often lifelong, which is not a requirement for all infectious diseases; some are acute and resolve quickly. Lastly, "hereditary" pertains to traits or disorders that are passed down genetically from parents to offspring, distinguishing it from infectious diseases that are caused by external infectious agents rather than genetic factors.