Virus with nucleic acid but without protein coat is

Options

A. Virion
B. Viroid
C. Capsid
D. Prion

Answer

To answer the question "Virus with nucleic acid but without protein coat is", we can analyze the options provided:

1. **Vireon**:
- A virion is the complete, infective form of a virus outside a host cell. It consists of a nucleic acid core (DNA or RNA) surrounded by a protein coat known as a capsid. Therefore, this option is incorrect because a virion has a protein coat.

2. **Viroid**:
- Viroids are the smallest infectious agents known, consisting solely of a short strand of circular RNA. They do not have a protein coat and are known to cause diseases in plants. This option fits the description of a virus with nucleic acid but without a protein coat. Thus, this is the correct answer.

3. **Capsid**:
- A capsid is the protein shell that encases the viral nucleic acid. Since it is a structure of a virus and not a type of virus itself, this option is incorrect.

4. **Prion**:
- Prions are infectious agents composed of protein, which can cause neurodegenerative diseases. They do not contain nucleic acids, making this option incorrect as well.

Based on this analysis, the correct answer to the question is **Viroid**.