Multiply by infecting host cells with genetic material.

• A. Bacteria
• B. Virus
• C. Fungus
• D. Prion

Answer: (B)

Viruses multiply by infecting host cells and hijacking the cell’s own machinery to replicate their genetic material and synthesize viral proteins. This obligate intracellular replication is what sets viruses apart: they can’t reproduce on their own and rely on a living cell to produce new virus particles. Bacteria reproduce through independent cellular division (binary fission), so they don’t need to invade a host cell just to multiply. Fungi typically reproduce via spores and growth, not by injecting genetic material into a host to take over its machinery. Prions are infectious proteins that spread by converting normal proteins into misfolded forms, without carrying genetic material to replicate.