Alexander Fleming discovered a type of that kills bacteria, which led to the development of Penicillin.

mold

Explanation:

Alexander Fleming was a Scottish physician and scientist. He was known for the development of penicillin.

Alexander Fleming discovered a type of mold that kills bacteria, which led to the development of Penicillin.

The mold created around itself a bacteria-free circle.

Fleming experimented further and named the active substance penicillin.

in situ hybridization has been widely used for research applications, including clinical cytogenetics, gene mapping, tumor biology and studies of chromosome evolution.