Which one is non-pathogenic ?

Options

A. Entamoeba coli
B. Entamoeba histolytica
C. E.gingivalis
D. Plasmodium ovale.

Answer

To determine which organism among the given options is non-pathogenic, we can analyze each one based on its known effects on human health.

### Step-by-Step Solution:

1. **Identify the Organisms**:
- The options provided are:
- Entamoeba coli
- Entamoeba histolytica
- E. gingivalis
- Plasmodium oval

2. **Analyze Each Organism**:
- **Entamoeba coli**: This protozoan is found in the human colon and is generally considered non-pathogenic. It does not cause disease in humans.
- **Entamoeba histolytica**: This organism is pathogenic and is known to cause amoebiasis, which can lead to amoebic dysentery.
- **E. gingivalis**: This protozoan is associated with gum disease (pyorrhea) and is considered pathogenic.
- **Plasmodium oval**: This species is known to cause malaria, which is a serious disease.

3. **Conclusion**:
- Among the four organisms, **Entamoeba coli** is the only one that is non-pathogenic. The other three (Entamoeba histolytica, E. gingivalis, and Plasmodium oval) are pathogenic and can cause diseases in humans.

### Final Answer:
**Entamoeba coli** is the non-pathogenic organism among the options provided.

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