While sorting through a pile of old Petri dishes, Alexander Fleming noticed that the mold in one of the dishes prevented bacteria from growing there. He decided to study the mold. Years later, other scientists used the active compound in this mold to develop the first antibiotic, penicillin. Which statement describes Alexander Fleming's scientific discovery?
1) He made a discovery that disproved all other theories.
2) He made a discovery by working with a group of scientists.
3) He made a discovery by carefully following and repeating a procedure.
4) He made a discovery without using all the steps of the scientific method.
