A worksheet function that is called by Excel can call back into Excel using the C API. An XLL command that is called by Excel can call the C API. DLL and XLL functions and commands that are called by VBA when VBA has itself been called by Excel can call the C API.
Cell Theory. The discovery of the cell was made possible by the invention of the microscope, which was made possible by improved lens-grinding techniques.Antoni van Leeuwenhoek (1632-1723), a Dutch tradesman, learned to grind lenses and assemble them into simple microscopes.nspired by Hooke's work, Leeuwenhoek began making microscopic examinations of his own. In 1678, he reported to the Royal Society that he had discovered little animals -- bacteria and protozoa -- in various samples. The society asked Hooke to confirm Leeuwenhoek's findings, and he did.
Matthias Schleiden helped to reject the theory of spontaneous generation by providing evidence of plants and how their organisms grew. Theodor Schwann Theodor Schwann discovered that plants are made up of cells using a microscope, which also supports the cell theory.ike Newton, the cell theory would not have been developed without the invention of the microscope. In order for Matthias Schleiden, Theodor Schwann, and Rudolf Virchow to create the cell theory, they needed the microscopes that Hans and Zacharias Jansen had invented prior to their discoveries.