Which tenet of cell theory is described by the following paragraph about the historical observations of cells?

the first cell was discovered in 1665 by robert hooke, who observed non-living cells of cork using a crude microscope and noted that they looked like tiny "rooms in which a monk might live." almost one decade later, anton van leeuwenhoek observed the first living cells, which he dubbed "animalcules," meaning "little animals." scientists continued to use these early microscopes to observe cells for over a century, and repeatedly found the cell to be the discrete unit of life. these observations culminated in 1824 with rene dutrochet declaring the cell to be "the fundamental element of organization."