The phenomenon that led to the discovery of penicillin involves:

From the given below,which one increases vitamin $B_{12}$ in our stomach and also plays a very beneficial role in checking disease-causing microbes?

Consider the following statements:
$I.$ Antibiotics are chemical substances produced by some microorganisms which can kill or retard the growth of other disease-causing microorganisms.
$II.$ Penicillin is the first antibiotic discovered by Alexander Fleming $(1928)$,while working on the bacterium $Staphylococcus$ $aureus$.
$III.$ The function of penicillin as an antibiotic was established by Ernst Chain and Howard Florey.
Which of the statements given above are correct?

What does $Rauwolfia$ $vomitoria$ produce?

Which of the following compounds are decomposed during putrefaction?

Proteins that kill the same or closely related species of bacteria are called