6. The commonly used method to improve the resolution of light microscope is () Increase the magnification of the eyepieces Stain the specimen Using a medium with a higher refractive index (e.g,,iil) Adjusting the condenser or add a red filter

The commonly used method to improve the resolution of a light microscope is to use a medium with a higher refractive index (e.g., oil). This is because a higher refractive index medium can reduce the amount of light scattering and increase the numerical aperture of the objective lens, leading to improved resolution.