Which of the following is not a mammalian character

Options

A. Hairy skin
B. Muscular diaphragm
C. 3- chamberd heart
D. RBSs enucleated

Explanation

To determine which of the following is not a mammalian character, we will analyze each option provided.

### Step-by-Step Solution:

1. **Identify the first option: Hairy Skin**
- Hairy skin is a characteristic feature of mammals. It helps in insulation and protection, especially in cold and wet climates. Therefore, this is a mammalian character.

2. **Identify the second option: Muscular Diaphragm**
- The muscular diaphragm is a key feature of mammals. It plays a crucial role in respiration by helping to expand and contract the thoracic cavity. Thus, this is also a mammalian character.

3. **Identify the third option: Three-Chambered Heart**
- Mammals possess a four-chambered heart, which consists of two atria and two ventricles. A three-chambered heart is characteristic of amphibians and some reptiles, not mammals. Therefore, this is not a mammalian character.

4. **Identify the fourth option: Arbis is Enucleated**
- In mammals, red blood cells (erythrocytes) are indeed enucleated, meaning they lack a nucleus. This is a characteristic feature of mammalian blood cells. Hence, this is a mammalian character.

### Conclusion:
Based on the analysis, the option that is not a mammalian character is **three-chambered heart**.

### Final Answer:
**Three-Chambered Heart** is not a mammalian character.

---