Which one of the following statements about viruses is correct

Options

A. Viruses possess their own metabolic system
B. All viruses contain both RNA and DNA
C. Viruses are obligate parasites
D. Nucleic acid of viruses is known as capsid

Answer

**Step-by-Step Solution:**

1. **Understanding Viruses**: Viruses are unique entities that are classified as obligate parasites. They cannot reproduce or carry out metabolic processes independently; they require a host cell to replicate and perform their functions.

2. **Characteristics of Viruses**: Viruses are generally inactive outside of a host organism. They do not possess their own metabolic systems and rely entirely on the host's cellular machinery for replication and protein synthesis.

3. **Genetic Material**: Viruses can contain either RNA or DNA as their genetic material, but not both simultaneously. This means that statements claiming that all viruses contain both RNA and DNA are incorrect.

4. **Capsid Structure**: The nucleic acid of a virus is not referred to as a protein capsid. The capsid is the protein coat that encases the viral genetic material, providing protection and aiding in the delivery of the nucleic acid into host cells.

5. **Identifying the Correct Statement**: Among the statements provided, the correct one is that viruses are obligate parasites. This means they cannot complete their life cycle or reproduce without a suitable host.

6. **Conclusion**: The correct statement about viruses is that they are obligate parasites.

**Final Answer**: Viruses are obligate parasites.

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