Microbiology is defined as the study of which of the following?

Microbiology is fundamentally defined as the study of micro-organisms, which include bacteria, viruses, fungi, and protozoa, among others. This field focuses on understanding how these tiny organisms function, their roles in various ecosystems, and their impacts on human health, agriculture, and industry. By studying these micro-organisms, scientists can gain insights into their behaviors, the diseases they may cause, and how to combat them, making it a crucial area of research and application in medicine and environmental science.

The other options refer to broader categories or unrelated subjects. For instance, macro-organisms pertain to larger living entities, like animals and plants, and are not the focus of microbiology. Living tissues involve the study of cellular structures in multicellular organisms, while chemical compounds deal with inorganic or organic creations that make up these organisms. Therefore, the core essence of microbiology lies specifically in the exploration and understanding of micro-organisms.