The most common carrier of communicable diseases is _______.

Options

A. ant
B. housefly
C. dragonfly
D. spider

Answer

**Step-by-Step Solution:**

1. **Understanding Communicable Diseases**: Communicable diseases are illnesses that can be transmitted from one person to another. They are often caused by microorganisms such as bacteria, viruses, or parasites.

2. **Identifying Carriers**: A carrier is an organism that can transmit a disease-causing pathogen to another organism. In this case, we need to identify which of the given options is the most common carrier of communicable diseases.

3. **Analyzing the Options**:
- **Option A: Ant** - While ants can carry pathogens, they are not the most common carriers of communicable diseases.
- **Option B: Housefly** - Houseflies are known to carry various pathogens, as they can land on feces and then on food, facilitating the spread of diseases.
- **Option C: Dragonfly** - Dragonflies are not known to be carriers of communicable diseases.
- **Option D: Spider** - Spiders do not typically carry diseases that are communicable to humans.

4. **Conclusion**: Based on the analysis, the housefly is the most common carrier of communicable diseases because it can easily transfer pathogens from feces to food, leading to infections through the fecal-oral route.

5. **Final Answer**: The most common carrier of communicable diseases is **housefly (Option B)**.

---