Amoxicillin is very effective for treating infections with Gram positive bacteria, and rarely causes side effects in humans. This is an example of:

A) altruism. B) narrow spectrum of action. C) a broad-spectrum antimicrobial. D) selective toxicity. E) antibiotic resistance.

The correct answer is D) selective toxicity

Explanation:

Selective toxicity refers to the ability of antimicrobial drug to selectively kill or harm the pathogen/microbes without harming the host cell. Therefore a drug who have selective toxicity rarely cause any side effect in the humans.

For example, penicillin is the drug that show selective toxicity because it acts on the cell wall of bacteria made up of peptidoglycan so it do not harm human cell as human cell do not have cell wall or peptidoglycan.

Therefore as amoxicillin rarely cause side effect in humans and effectively treat infection by gram-positive bacteria therefore it is an example of selective toxicity.