Final answer:
Microscopes are characterized by their magnification, resolution, and illumination methods, which collectively allow the detailed examination of microscopic samples.
Step-by-step explanation:
The observable characteristics of microscopes used for examining samples are magnification, resolution, and illumination. Magnification refers to the capability of the microscope to enlarge the image of an object compared to its real size, allowing an image to appear several times larger than it does to the nak-ed eye. Light microscopes, which are often used in undergraduate labs, usually magnify up to 400 times and can increase to 1,000 times with oil immersion lenses for the study of smaller structures like prokaryotic cells. On the other hand, resolution, or the resolving power, is the ability of a microscope to distinguish two adjacent structures as separate entities, enabling the user to see the specimen with better clarity and detail. Lastly, illumination techniques such as transmitted light, dark field, and phase contrast are applied to light up the specimen for clearer visualization.