Capsid is

Options

A. Genetic material of virus
B. Protein cover of virus
C. Extra genetic material of bacterium
D. House keeping genome of bacterium.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the definition of "capsid." It is important to identify what a capsid is in the context of viruses.

2. **Identifying the Options**: The options provided are:
- A) Genetic material of virus
- B) Protein covers of virus
- C) Extra genetic material of bacterium
- D) Housekeeping genome of bacteria

3. **Analyzing Each Option**:
- **Option A**: Genetic material of virus - This is incorrect because the capsid is not the genetic material itself; it is a structure that protects the genetic material.
- **Option B**: Protein covers of virus - This is correct. The capsid is indeed a protein shell that encases the genetic material of the virus.
- **Option C**: Extra genetic material of bacterium - This is incorrect because capsids are not related to bacterial genetic material.
- **Option D**: Housekeeping genome of bacteria - This is also incorrect as it does not pertain to the definition of a capsid.

4. **Conclusion**: Based on the analysis, the correct answer is Option B: "Protein covers of virus."

5. **Final Answer**: Capsid is the protein covering of a virus that protects its genetic material (DNA or RNA).

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