glass making astronomy medicine teaching
I gave my students this multiple choice question: In the 1600s a scientist named Anton van Leeuwenhoek worked toward improving microscopes and created his own lenses. With his microscopes, Leeuwenhoek discovered bacteria and muscle fibers. Which type of job benefited most from these discoveries?

Only one answer is correct among these 4 choices:
- glass making
- astronomy
- medicine
- teaching

Could you tell me which one is correct?

medicine