In the context of viruses, why does a virus need a host cell to replicate?

• A. Because viral genomes cannot be replicated unless they are first converted into host chromosomes by meiosis.
• B. Because viruses must obtain a nucleus from the host cell in order to form their capsid proteins.
• C. Because viruses need host cell mitochondria to directly translate viral mRNA into protein inside the mitochondria.
• D. Because it lacks the cellular machinery (e.g., ribosomes, ATP-generating pathways, and many enzymes) needed to synthesize viral proteins and copy its genome independently.

Answer: (D)