What is the main use of a microscope?

The primary function of a microscope is to magnify objects for clearer viewing. This magnification allows for the observation of structures and details that are not visible to the naked eye. Microscopes are essential tools in various fields, including biology, medicine, and environmental science, as they enable scientists and specialists to study microorganisms, cells, and tissues in great detail. By increasing the size of the specimen being examined, a microscope facilitates thorough examination and analysis, which is crucial for research, diagnostics, and quality control.

The other options, while relevant to different scientific procedures, do not directly relate to the main function of microscopy. Measuring chemical reactions involves different techniques and instruments, filtering water is a physical process that does not require magnification, and testing food for pathogens typically employs various methods, including culturing or molecular techniques, rather than solely relying on visual magnification. Each of these tasks serves important roles in environmental health or laboratory settings but does not encapsulate the fundamental purpose of a microscope.