Which statement about antibiotics is true?

• A. They cure viral infections such as the flu
• B. They are effective against bacteria, not viruses
• C. They are effective against all microorganisms
• D. They boost the immune system to fight infections

Answer: (B)

Antibiotics are designed to treat infections caused by bacteria by targeting processes that bacteria rely on, such as building their cell walls or making proteins and copying DNA. Viruses, on the other hand, have a very different biology and don’t have the same targets as bacteria, so antibiotics can’t effectively kill or stop them. That means they won’t cure viral infections like the flu.

So the statement that antibiotics are effective against bacteria, not viruses, is the true one. They aren’t effective against all microorganisms—fungi, parasites, and some resistant bacteria require other drugs—and they don’t boost the immune system or work as vaccines.