Answer:
The discovery of cells by Robert Hooke in 1665 and the development of the cell theory by Matthias Schleiden and Theodor Schwann in 1838-1839 were separated by a 163-year gap because the scientific method and technology during this period did not allow for the systematic study and understanding of cells and their functions.
After Hooke's discovery of cells in cork, the scientific community was not immediately able to recognize the importance of the discovery. It took several decades for scientists to recognize that all living organisms were composed of cells, and this realization paved the way for the development of the cell theory.
The study of cells was also limited by the lack of proper technology and equipment during this period. Microscopes were not yet advanced enough to allow scientists to see the fine details of cells, and it was only with the development of more powerful microscopes in the 19th century that scientists were able to study cells in greater detail and develop the cell theory.
Furthermore, scientific progress during this time was slow due to the lack of collaboration and communication between scientists, as well as the limited funding and support for scientific research. It was only with the establishment of scientific societies and universities in the 19th century that scientific research became more systematic and collaborative, leading to the rapid advancement of scientific knowledge, including the development of the cell theory.