Which one of the following represents characteristic of birds?

Options

A. Strong muscles
B. Light bones
C. Hollow bones
D. All of these

Answer

To determine the characteristics of birds, we can analyze the options provided and understand how they relate to the unique adaptations birds have for flying. Here’s a step-by-step solution:

### Step-by-Step Solution:

1. **Identify the Characteristics of Birds**: Birds are known for their ability to fly, which requires specific adaptations in their body structure.

2. **Examine the Options**: The options given are:
- Strong muscles
- Light bones
- Hollow bones
- All of these

3. **Analyze Each Option**:
- **Strong Muscles**: Birds have strong muscles, particularly in their wings, which are essential for flapping and generating lift during flight.
- **Light Bones**: Birds have lightweight bones that reduce their overall body weight, making it easier for them to take off and stay airborne.
- **Hollow Bones**: Many birds have hollow bones, which further decreases their weight without sacrificing strength, allowing for efficient flight.

4. **Conclusion**: Since all three characteristics (strong muscles, light bones, and hollow bones) are essential for birds to fly, the correct answer is "All of these".

### Final Answer:
**All of these** represents characteristics of birds.

---