What is a pathogen?

A pathogen is defined as a microorganism that can cause disease. This includes a range of entities such as bacteria, viruses, fungi, and parasites. Pathogens are notorious for their ability to disrupt normal bodily functions, leading to illness or various health complications.

Understanding this definition is crucial, as it clarifies the role these microorganisms play in health and disease. The identification of pathogens is essential in fields such as medicine, microbiology, and public health, enabling the development of treatments, vaccines, and preventive measures to combat infections and diseases they cause.

While some microorganisms are beneficial to human health, as seen with probiotics or certain bacteria that contribute to digestion, pathogens specifically refer to those that pose a threat to health. Other options mentioned focus on beneficial microorganisms or limit the definition to only harmful bacteria, which does not encompass the full range of disease-causing agents. Thus, option C accurately encapsulates the broad and essential definition of pathogens in the context of health and disease.