Polio, influenza, measles, hepatitis -B are all caused by

Options

A. bacteria
B. virus
C. fungi
D. protozoans

Explanation

To determine what causes polio, influenza, measles, and hepatitis B, we can follow these steps:

### Step 1: Identify the diseases
- The diseases mentioned are polio, influenza, measles, and hepatitis B.

### Step 2: Understand the types of pathogens
- Pathogens can be classified into different categories: bacteria, viruses, fungi, and protozoa.

### Step 3: Analyze each disease
- **Polio**: Caused by the poliovirus.
- **Influenza**: Caused by the influenza virus.
- **Measles**: Caused by the measles virus.
- **Hepatitis B**: Caused by the hepatitis B virus.

### Step 4: Determine the common factor
- All four diseases are caused by viruses. Viruses are non-living entities that require a host to survive and reproduce.

### Step 5: Conclusion
- Therefore, polio, influenza, measles, and hepatitis B are all caused by viruses.

### Final Answer
Polio, influenza, measles, and hepatitis B are all caused by **viruses**.

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