Which one of the following is discovered by Robert Hook earlier than protoplast?

Which one of the following is discovered by Robert Hook earlier than protoplast?

Explanation

Robert Hooke discovered the "cell wall" in 1665 when he observed dead cork cells under a microscope.

He named these small compartments "cells" because they reminded him of the rooms in a monastery.

The concept of "protoplast," which refers to the living contents of a cell, was discovered later.