Question

What did Leeuwenhoek use that enabled him to see bacteria?

Answer 1

He used a single lensed microscope that he made himself to look at bacteria.

Answer 2

he used single-lens microscopes, which he made, to make the first observations of bacteria and protozoa. His extensive research on the growth of small animals such as fleas, mussels, and eels helped disprove the theory of spontaneous generation of life.