A biological agent of the disease is

Options

A. Vitamin deficiency
B. Virus
C. Spores
D. Carbohydrate deficiency

Answer

**Step-by-Step Solution:**

1. **Understanding Biological Agents:**
- Biological agents of disease are known as pathogens. These are microorganisms that can cause diseases in humans and other living organisms.

2. **Identifying the Options:**
- The options provided are:
A. Vitamin deficiency
B. Virus
C. Spores
D. Carbohydrate deficiency

3. **Analyzing Each Option:**
- **A. Vitamin deficiency:** This is not caused by a biological agent but is a deficiency disease resulting from a lack of essential vitamins in the diet.
- **B. Virus:** Viruses are indeed biological agents. They are small infectious agents that can replicate within living organisms and are known to cause various diseases.
- **C. Spores:** While spores can be associated with certain pathogens (like fungi), they themselves are not classified as biological agents of disease in the same way that viruses are.
- **D. Carbohydrate deficiency:** Similar to vitamin deficiency, this is also a deficiency disease and not caused by a biological agent.

4. **Conclusion:**
- Based on the analysis, the only option that qualifies as a biological agent of disease is **B. Virus**.

**Final Answer:**
- The biological agent of the disease is **B. Virus**.

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