Birds differ from nonchordates due to presence of

Options

A. True coelom
B. Bilateral symmetry
C. Feathery wings
D. Deuterostomic body plan

Answer

To answer the question of how birds differ from nonchordates, we can follow these steps:

### Step 1: Identify the Key Characteristics of Birds
Birds are a specific group of animals that possess certain unique features that distinguish them from nonchordates. These features include:

- Presence of a vertebral column (backbone)
- A four-chambered heart
- Feathery wings

### Step 2: Compare with Nonchordates
Nonchordates are a diverse group of animals that do not have a backbone. They include organisms such as insects, mollusks, and cnidarians. Key differences include:

- Nonchordates do not have a vertebral column.
- They typically do not have a four-chambered heart.
- They lack the specialized structure of wings that are adapted for flight.

### Step 3: Focus on Unique Features
Among the features listed, the most distinctive characteristic that sets birds apart from nonchordates is the presence of **feathery wings**. This adaptation is specifically evolved for flight and is not found in nonchordates.

### Step 4: Eliminate Other Options
- **True coelom**: This is found in both chordates and some nonchordates, so it cannot be used to differentiate birds from nonchordates.
- **Bilateral symmetry**: This is a common trait in many animals, including both chordates and nonchordates.
- **Deuterostomic body plan**: This refers to the embryonic development where the anus forms before the mouth, which is found in some nonchordates.

### Conclusion
The correct answer to how birds differ from nonchordates is due to the presence of **feathery wings**.

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