What is common among dodo, penguin and Rhea?

Options

A. These are flightless birds
B. These are running birds
C. These are migratory birds
D. These have four toes in their feet

Answer

### Step-by-Step Solution:

1. **Identify the Birds**:
- The three birds in question are the dodo, penguin, and rhea.
- The dodo is an extinct bird, while the penguin and rhea are still existing species.

2. **Determine Characteristics**:
- The dodo was known for being flightless and lived on the island of Mauritius.
- Penguins are also flightless birds, adapted for swimming rather than flying.
- Rhea is a large flightless bird native to South America, often compared to the ostrich.

3. **Analyze Common Features**:
- All three birds are classified as flightless birds.
- They lack the adaptations necessary for flight, such as a keel (the extension of the breastbone), wings, and other features typical of flying birds.

4. **Evaluate Other Options**:
- **Running Birds**: While the rhea and ostrich are good runners, penguins are not, as they have flippers for swimming.
- **Migratory Birds**: Only some penguin species are migratory, while the dodo and rhea are not.
- **Toe Count**: Penguins have webbed feet, and rheas have two toes, making this option incorrect.

5. **Conclusion**:
- The commonality among the dodo, penguin, and rhea is that they are all flightless birds.

### Final Answer:
The common feature among dodo, penguin, and rhea is that they are all flightless birds.

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