A particular antibiotic kills 99% of a bacterial population. What will be the result of the continued application of this antibiotic?

over time the antibiotic will become less effective against bacteria.

Explanation:

A new antibiotic can kill a greater percentage of bacteria because very less bacteria is resistant towards that antibiotic but when that antibiotic is used continuously for a long time then some bacteria develop resistance against that antibiotic and due to natural selection these bacteria are selected.

So if a particular antibiotic kills 99% of a bacterial population so the continuous use of this antibiotic will allow some bacteria to evolve resistance against it. Then these resistant bacteria will be selected by natural selection and over time the antibiotic will become less effective against bacteria.