Correct Answer: Robert Hooke
Subject: 2025
Explanation: <b>Key Fact</b><br>Robert Hooke discovered cells in 1665 while examining a thin slice of cork under a microscope.<br><br><b>Additional Info</b><br>Topic: Cell Biology.<br><br><b>Why the other options are wrong</b><br>Option A: Correct.<br>Option B: Robert Koch is known for his work on bacterial disease etiology and tuberculosis.<br>Option C: Edward Jenner developed the smallpox vaccine.<br>Option D: Louis Pasteur discovered pasteurization and principles of vaccination.<br><br><b>Exam Trick</b><br>Remember Hooke = Cork cell discovery (1665).<br><br><b>Final Answer</b><br>Option A — Robert Hooke.