In the 1830 s two researchers, Theodor Schwann and Mattias Schleiden saw the universality of cells in living things.
All cells arise from pre-existing cells.
Electron Microscopes can resolve in Angstroms. They use magnets and beams of electrons in place of a visible light. There are two types of electron microscopes, transmission and scanning. Transmission electron microscopes are used for viewing internal structures of cells. Before a specimen is viewed, it must be fixed then sliced very thinly so that the electron beam can be passed through it.