Which of the following organism has open type of circulation

Options

A. Earth worm
B. Leech
C. Cockroach
D. Octopus

Answer

To determine which organism has an open type of circulation, we will analyze the options provided based on the characteristics of their circulatory systems.

### Step-by-Step Solution:

1. **Understand Open Circulation**:
- Open circulation is a type of circulatory system where the blood is not confined exclusively within blood vessels. Instead, it is pumped into a cavity called the hemocoel, where it bathes the organs directly.

2. **Evaluate the First Option - Earthworm**:
- Earthworms have a closed circulatory system. In this system, blood is contained within blood vessels, and it is pumped through these vessels. Therefore, this option is incorrect.

3. **Evaluate the Second Option - Leech**:
- Similar to earthworms, leeches also possess a closed circulatory system. Their blood circulates within vessels. Thus, this option is also incorrect.

4. **Evaluate the Third Option - Cockroach**:
- Cockroaches have an open circulatory system. Their blood (hemolymph) is not contained entirely within vessels; it flows freely in the hemocoel. Therefore, this option is correct.

5. **Evaluate the Fourth Option - Octopus**:
- Octopuses have a closed circulatory system, where blood is contained within vessels. Hence, this option is incorrect.

6. **Conclusion**:
- Based on the evaluations, the organism with an open type of circulation is the **Cockroach**.

### Final Answer:
The organism that has an open type of circulation is the **Cockroach**.