Answer:
The correct answer is- antibiotics
Explanation:
Antibiotic is the substance that is used to fight the invading bacteria by slowing down their growth or by killing them. The first antibiotic was penicillin discovered by Alexander Fleming in 1928.
Penicillin was able to control the growth of gram-positive bacteria by ceasing the transpeptidation reaction in gram-positive bacteria. By doing this penicillin stops bacteria to produce new cell wall which ultimately results in the killing of bacteria.
Different antibiotic have different targets in bacteria which allow antibiotics to destroy the invading bacteria or to slow their multiplication rate.