The cell theory was

A: developed by Robert Hooke
B: developed before microscopes were invented
C: developed only after electron microscopes became widely used
D: developed by many scientists over many years
Is the answer A?

Incorrect

Robert Hooke was the person who coined the word "cell."

Would it be D then? @lucina

Yes :)

Yes, the correct answer is A: developed by Robert Hooke. The cell theory, which states that all living organisms are composed of cells, cells are the basic units of structure and function in living organisms, and cells arise from pre-existing cells, was indeed developed by Robert Hooke. He is credited with the discovery of cells in 1665 when he observed thin slices of cork under a microscope and described the box-like structures he saw as "cells" because they reminded him of the cells, or small rooms, found in monasteries.