What Robert Hooke had discovered in the thin section of the cork as a cell was actually

Robert Hooke, in his investigations of a thin section of cork in the mid-17th century, discovered what he termed "cells." He observed under a microscope that the cork had a cellular structure, resembling the small rooms (cells) in a monastery. However, it's important to note that what Hooke actually observed were not living cells but rather the cell walls of dead plant tissue. The cells in the cork did not contain any protoplasm or other living components that make up living cells. Instead, they were merely the empty spaces surrounded by the rigid walls of plant cells.

Hooke's discovery was foundational in biology as it led to the development of the cell theory, which states that all living organisms are composed of cells. His work highlighted the importance of the microscope in biological research and opened the door for advancements in cell biology and microscopy.