13 chambered heart is present in :

Options

A. Earthworm
B. Cockroach
C. Rat
D. Leech

Answer

To determine which organism has a 13-chambered heart among the options provided (earthworm, cockroach, rat, leech), we can analyze the heart structure of each organism step by step.

### Step-by-Step Solution:

1. **Understanding Heart Structures**:
- Different organisms have different types of hearts. For example, some have simple tubular hearts, while others have more complex structures.

2. **Analyzing the Options**:
- **Earthworm**: Earthworms have a closed circulatory system with multiple aortic arches that function similarly to a heart, but they do not have a 13-chambered heart.
- **Cockroach**: The cockroach has a tubular dorsal heart that is composed of multiple chambers (typically 13), which are open at the ends with structures called ostia. This heart is responsible for pumping hemolymph throughout the body.
- **Rat**: Rats, being mammals, have a four-chambered heart consisting of two atria and two ventricles, which is not what we are looking for.
- **Leech**: Leeches have a simple circulatory system and do not possess a heart with 13 chambers.

3. **Conclusion**:
- After analyzing the heart structures of the given organisms, it is clear that the **cockroach** has a 13-chambered heart.

### Final Answer:
The 13-chambered heart is present in the **cockroach**.

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