Final answer:
Ribosomes are not visible using a light microscope because they are too small and their resolution is beyond the limit of the microscope's capability. Electron microscopes are used instead because they have a higher resolution and can magnify the image of ribosomes to a visible level.
Step-by-step explanation:
Ribosomes are not visible using a light microscope because they are very small and their resolution is beyond the limit of the light microscope's capability. The wavelength of visible light is around 400-700 nanometers, while ribosomes are only about 20-30 nanometers in size.
Instead, electron microscopes are used to visualize ribosomes because they use a beam of electrons instead of light waves. Electron microscopes have a much higher resolution and can magnify the image of ribosomes to a level that is visible to scientists.
Therefore, while light microscopes are useful for studying larger cellular structures, they cannot provide the necessary level of detail to visualize ribosomes.