Binary fission is found in

Options

A. Vorticella
B. Planaria
C. Paramecium
D. All of these

Answer

### Step-by-Step Solution:

1. **Understanding Binary Fission**:
- Binary fission is a type of asexual reproduction where a single organism divides into two identical daughter organisms. This process involves the duplication of genetic material (DNA) followed by the division of the cytoplasm (cytokinesis).

2. **Identifying the Organisms**:
- The question provides four options:
- Vorticella
- Planaria
- Paramecium
- All of these

3. **Analyzing Each Organism**:
- **Vorticella**: This is a protozoan that reproduces asexually through binary fission.
- **Planaria**: While planaria are flatworms that can reproduce asexually through regeneration, they do not typically reproduce by binary fission.
- **Paramecium**: This is also a protozoan that reproduces asexually through binary fission.

4. **Conclusion**:
- Among the given options, Vorticella and Paramecium reproduce by binary fission. Planaria does not reproduce by binary fission; hence, it is not included. Therefore, the correct answer is that binary fission is found in Vorticella and Paramecium, but not Planaria.

5. **Final Answer**:
- The correct option is **Vorticella and Paramecium**. However, if the question implies that "all of these" refers to the organisms that can reproduce asexually, then the answer could be interpreted as **All of these**, but strictly speaking, only Vorticella and Paramecium reproduce by binary fission.