Final answer:
Decreased slice thickness directly improves axial resolution by reducing the amount of overlap between structures at different depths, resulting in a sharper and more detailed image.
Step-by-step explanation:
The question asks about improving the axial resolution, which is the capability to distinguish two points located along the axis of the microscope's beam path. Among the given options, Decreased slice thickness directly helps improve axial resolution. This is because a thinner slice reduces the amount of overlap between structures at different depths, which can make the image appear blurrier. Therefore, by decreasing slice thickness, the depth of field is reduced, and axial resolution is improved, resulting in a sharper image.
In the context of magnification and resolution, it's important to understand that simply increasing magnification does not necessarily improve resolution. Factors like numerical aperture and wavelength of the light used also play vital roles in determining resolution. Shorter wavelengths and higher numerical apertures lead to better resolution because they allow for the differentiation of finer details.