What is one key characteristic of pathogenic microorganisms?

Pathogenic microorganisms are defined by their ability to cause disease in hosts. This characteristic sets them apart from other types of microorganisms, which may have no effect, provide benefits, or even be harmful in other contexts. Pathogens can invade the host's system, evade immune responses, and multiply, leading to various diseases ranging from mild infections to severe health complications. Understanding this key characteristic is vital in fields like microbiology, healthcare, and mortuary science, as it helps in identifying, preventing, and controlling infections.

While microorganisms are indeed found in various environments, not all of them are pathogenic or affect health negatively. Some microorganisms play essential roles in ecosystems or human health, such as those involved in digestion or protective functions against harmful bacteria. Additionally, although some microorganisms thrive in water, many pathogenic varieties can also be found in soil, air, and within hosts themselves. Thus, the ability to cause disease is the defining feature of pathogenic microorganisms.