Final answer:
The word that completes the analogy 'Microphone : Loud :: Microscope :' is 'Magnify.' A microscope's purpose is to magnify objects, with some types like electron microscopes reaching magnifications of up to 1,000,000 times.
Step-by-step explanation:
The analogy given in the question is comparing a microphone's function to a microscope's function. The microphone amplifies sound, making it louder, while the microscope does something similar but with visual things. Therefore, the word that completes the analogy 'Microphone : Loud :: Microscope :' is Magnify, as the primary function of a microscope is to magnify images and use the properties of light to create useful images of small objects.
A light microscope can magnify images up to about 1000 times using visible or ultraviolet light. Types of microscopes like simple light microscopes and electron microscopes can magnify even more. For instance, an electron microscope can magnify up to 1,000,000 times. This level of magnification allows scientists to see details of cells and viruses, such as the flu virus, which is about 100 nanometers in diameter. The magnification and resolving power are critical in understanding the structure and function of cells.