Final answer:
The ability to distinguish between two closely positioned objects is called resolution, a term central to the use of microscopes in biology. A higher resolution indicates a lens's ability to display two point objects as separate with greater clarity, which is typically considered when magnifying at 1,000 times using oil immersion lenses, although the practical resolution limit is 0.2 µm.
Step-by-step explanation:
The ability to distinguish between two closely positioned objects is known as resolution. This term is frequently introduced in biology laboratories when students begin to use microscopes. Resolution refers to a lens's capability to produce distinct images of two nearby point objects, with the smallest distance at which they can be separated and still observed as discrete signifying a higher resolution. This is crucial in the field of microscopy, where resolving power is a key characteristic that describes how close two objects can be while still being visually separable. The defining equation for the resolving power of a lens is derived from the Rayleigh criterion. In the study of cellular structures, particularly when working with oil immersion lenses, the magnification can increase to 1,000 times. Nevertheless, even with high magnification, the practical limit of resolution for standard optical microscopes remains around 0.2 µm.