Two micronuclei occur in

Options

A. Paramecium aurelia
B. Paramecium caudatum
C. Paramecium multimicronucleatum
D. Balantidium coli.

Answer

To solve the question "Two micronuclei occur in," we will analyze the provided options step by step.

### Step-by-Step Solution:

1. **Understanding Micronuclei**:
- Micronuclei are small nuclei that are typically involved in the reproductive process of certain protists. They are distinct from macronuclei, which are larger and usually involved in everyday cellular functions.

2. **Identifying the Options**:
- The options given are:
1. Paramecium aurelia
2. Paramecium caudatum
3. Paramecium multimicronucleatum
4. Balantidium coli

3. **Analyzing Each Option**:
- **Paramecium aurelia**: This organism is known to have two micronuclei along with two macronuclei. This fits the criteria of the question.
- **Paramecium caudatum**: This organism undergoes mitosis but does not specifically have the characteristic of having micronuclei and macronuclei as described in the question.
- **Paramecium multimicronucleatum**: As the name suggests, this organism has multiple micronuclei, which exceeds the two micronuclei mentioned in the question.
- **Balantidium coli**: This organism primarily contains macronuclei and does not exhibit the presence of micronuclei.

4. **Conclusion**:
- Based on the analysis, the organism that has two micronuclei is **Paramecium aurelia**. Therefore, the correct answer is option **1**.

### Final Answer:
**Paramecium aurelia** (Option 1) is the organism that has two micronuclei.