Which is the largest known virus?

Options

A. Foot and mouth disease virus
B. measles virus
C. Variola virus
D. Influenza virus

Answer

To determine which is the largest known virus, we can follow these steps:

### Step 1: Identify the Options
The question provides four options:
- A) Foot and Mouth Disease Virus
- B) Measles Virus
- C) Variola Virus
- D) Influenza Virus

### Step 2: Research the Viruses
We need to gather information about the size of each virus listed in the options:
- **Foot and Mouth Disease Virus**: Generally around 22-30 nanometers.
- **Measles Virus**: Approximately 100-300 nanometers.
- **Variola Virus**: Known to be larger, measuring approximately 302-350 nanometers.
- **Influenza Virus**: Typically around 80-120 nanometers.

### Step 3: Compare the Sizes
From the gathered information, we can compare the sizes:
- The **Foot and Mouth Disease Virus** is the smallest.
- The **Measles Virus** is larger than the Foot and Mouth Disease Virus but smaller than the Variola Virus.
- The **Influenza Virus** is also smaller than the Variola Virus.
- The **Variola Virus** is the largest among the listed viruses.

### Step 4: Conclusion
Based on the size comparison, the largest known virus is the **Variola Virus**, which causes smallpox.

### Final Answer
The correct answer is **C) Variola Virus**.

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