the development of microscope...(quick)

The development of microscope allowed us to discover and learn about things we cant see with our eyes. The first microscope was develope by a Antony Van Leeuwenhook, he was the first to look at living cells under a microscope. He found microbes in pond water but did not do any further research on microscopes and the micorbe that he discovered.
When the light microscope was developed it allowed Biologist at the time to look at the structure of cells, cell walls, nucleus, etc. This has contributated alot to the development of our knowledge in living cells. However, the light microscope does not provide a high enough resolution to see all the detailed parts of the cell. eg. Phospholipid Bilayer.
Later the electron micoscopes are developed, having the electrons instead of the light as the source of energy. An image with a much higer resolution can now be produced, it is untill then that more detailed structures are discovered. eg. Microvilli in epthelial cells.

This is all about biology, sorry can only help you this much as i only study biology and chemistry.