What best describes microorganisms?

Microorganisms are best described as living entities that play essential roles in various ecosystems and biological processes. They encompass a diverse range of organisms, including bacteria, viruses, fungi, and protozoa. While some microorganisms are indeed harmful and can cause infections, many are beneficial and necessary for processes such as digestion, nutrient cycling, and maintaining ecological balance.

In specific contexts, these microorganisms exist and thrive in environments that may be extreme or unique. They are vital for the survival of many species, including humans, as they contribute to health by aiding in digestion, producing vitamins, and protecting against pathogenic organisms. This broader understanding highlights the importance of microorganisms in maintaining life and supporting various ecosystems rather than limiting them to being only harmful or dead elements.