What are microorganisms commonly referred to as?

Microorganisms are commonly referred to as "germs and microbes" because this term encompasses a wide variety of tiny living organisms that can be found in diverse environments, including bacteria, viruses, fungi, and protozoa. The term "germs" often conveys the idea of microorganisms that can cause disease, while "microbes" encompasses both harmful and beneficial organisms. This broad terminology helps in explaining the role microorganisms play in health, disease, digestion, and ecological functions.

The other options refer to specific biological entities or compounds. Enzymes, for example, are proteins that catalyze biochemical reactions but are not synonymous with microorganisms. Pathogens represent a subset of microorganisms that specifically cause disease, but the term "germs and microbes" includes all types of microorganisms beyond just those that are harmful. Macromolecules are large complex molecules (like proteins, nucleic acids, and polysaccharides) that serve various roles in biological systems but do not refer to organisms themselves. Therefore, the most accurate and comprehensive term that describes microorganisms in general usage is indeed "germs and microbes."