Microorganisms, often referred to as microbes, are tiny living organisms that are too small to be seen with the naked eye. They include a diverse group of organisms such as bacteria, viruses, fungi, protozoa, and algae. Microorganisms can be found in almost every habitat on Earth, including soil, water, air, and inside other organisms. They play crucial roles in various ecological processes, including decomposition, nitrogen fixation, and as part of the food chain. Some microorganisms are beneficial and essential for processes like fermentation and digestion, while others can cause diseases.