How is the term 'magnification' best defined?

The term 'magnification' refers to the increase in the apparent size of an object when viewed through a microscope or other optical instruments. It describes the ability of an optical system to enlarge the image of a specimen, allowing details that are not visible to the naked eye to be observed. This is crucial in biology and many other fields, as it enables researchers to study cells, tissues, and small organisms in depth and observe structures such as organelles, which are essential for understanding cellular functions and processes.

In contrast, other definitions provided, such as the number of cells in a culture, pertain to quantification rather than the optical enlargement of an image. The density of a substance is a physical property related to mass and volume, while the total volume of a solution involves measurement that does not relate to the visual enlargement of objects. Thus, the correct definition of magnification is indeed the increase in the apparent size of an object, which is fundamental in microscopy.