Answer:
1. While observing cork through his microscope, Hooke saw tiny boxlike cavities, which he illustrated and described as cells.
2. D. Robert Koch developed a way to prove that a specific microbe caused a particular disease. Matthias Jakob Schleiden suggested that ALL plants are made of cells.
3. Anton van Leeuwenhoek is another scientist who saw these cells soon after Hooke did. He made use of a microscope containing improved lenses that could magnify objects almost 300-fold, or 270x. ... He also found for the first time the sperm cells of animals and humans.
4. Antonie van Leeuwenhoek used single-lens microscopes, which he made, to make the first observations of bacteria and protozoa. His extensive research on the growth of small animals such as fleas, mussels, and eels helped disprove the theory of spontaneous generation of life.
Explanation: