How was penicillin used in history ? Well they discovered that it worked and started using it for helping save lives in ww2 A good example of this is D-Day
How does penicillin affect us today ? It affects us today in the sense that even though it is uncommon for someone to die from an infection, it helps them loose the small risk of dying and helps them loose the infection quicker.
Penicillin actually came from a fungus called "Penicillium Fungi".
It was an accident that Alexander found penicillin.
A medical student named Ernest Dushehe actually found the fungus in the late 19th century, but then Alexander Fleming refounded it in 1928 for its antibiotic properties.