Which of the following is a basic characteristic of a virus?

• A. It reproduces by binary fission.
• B. It is composed only of proteins and lacks nucleic acids.
• C. It requires a host cell to replicate.
• D. It can carry out metabolic processes independently.

Answer: (C)

Verified step by step guidance

1. Understand that viruses are unique infectious agents that differ fundamentally from cellular life forms such as bacteria and eukaryotes.
2. Recall that viruses cannot reproduce on their own because they lack the cellular machinery necessary for independent replication.
3. Recognize that viruses require a host cell to replicate, meaning they must infect a living cell and hijack its machinery to produce new virus particles.
4. Eliminate options that describe characteristics of cellular organisms, such as reproduction by binary fission or carrying out metabolic processes independently, since viruses do not perform these functions.
5. Note that viruses contain nucleic acids (DNA or RNA) and proteins, so the statement that they are composed only of proteins and lack nucleic acids is incorrect.