Which of the following is the exclusive feature of the birds

Options

A. 4 - chambered heart
B. Homoeothermic
C. Fore limbs modified into wings
D. Presence of feathers

Answer

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks for an exclusive feature of birds. This means we need to identify a characteristic that is unique to birds and not shared with other animal groups.

2. **Evaluate Each Option**:
- **Option 1: 4 Chambered Heart**: Birds do have a 4 chambered heart, which consists of two atria and two ventricles. However, this feature is not exclusive to birds as mammals and some reptiles (like crocodiles) also possess a 4 chambered heart. Therefore, this option is not correct.

- **Option 2: Homeothermic Animals**: Birds are indeed homeothermic (warm-blooded), but this characteristic is also found in mammals, including humans. Thus, this is not an exclusive feature of birds.

- **Option 3: 4 Limbs Modified into Wings**: While birds do have their forelimbs modified into wings, this feature is not exclusive to them. Other animals, such as bats, also have modified limbs for flight. Therefore, this option is also incorrect.

- **Option 4: Presence of Feathers**: This is the key feature that is exclusive to birds. Feathers are unique to the class Aves and are not found in any other group of animals. Thus, this is the correct answer.

3. **Conclusion**: The exclusive feature of birds is the presence of feathers.

**Final Answer**: The exclusive feature of birds is the presence of feathers.

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