Macro and micronucleus are the characteristic feature of

Options

A. Paramecium and Vorticella
B. Opelina and Nictotihirus
C. Hydra and Ballantidium
D. Vorticella and Nictothirus

Explanation

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the organisms that possess both macro and micronucleus, which are characteristic features of certain protists.

2. **Defining Macro and Micronucleus**:
- The macronucleus is a large nucleus that controls the metabolic functions of the cell and is involved in asexual reproduction.
- The micronucleus is smaller and contains the genetic material (genome) necessary for sexual reproduction.

3. **Identifying the Condition**: The presence of both a macronucleus and a micronucleus in a single organism is referred to as "dimorphic nuclei."

4. **Listing the Options**: The options provided are:
- Paramecium and Vorticella
- Obelia and Nicothera
- Hydra and Balantidium
- Vorticella or Nicothera

5. **Analyzing the Options**:
- Paramecium and Vorticella are known to have dimorphic nuclei (macronucleus and micronucleus).
- The other options (Obelia, Nicothera, Hydra, and Balantidium) do not typically exhibit this characteristic.

6. **Conclusion**: Based on the analysis, the correct answer is **Paramecium and Vorticella** as they are the organisms that possess both macro and micronucleus.

### Final Answer:
**Paramecium and Vorticella**

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