Question

in which specimen were cells first identified?
○ microorganism
○ cork bark
○ dna
○ mitochondrion

Explanation:

Robert Hooke first identified cells in cork bark (from a cork oak tree) using a microscope, seeing the empty cell walls as "cells". Microorganisms were later observed, DNA and mitochondria are cellular components, not the first specimen with cells identified.

Answer:

B. cork bark