Closed blood vascular system found in

Options

A. Bombyx
B. Sepia
C. Balanoglossus
D. Ascidia

Answer

To determine which organism has a closed blood vascular system among the options provided, we can analyze each option step by step.

### Step-by-Step Solution:

1. **Identify the Options**: The options given are:
- A. Bombyx
- B. Sepia
- C. Balenoglossus
- D. Ascidia

2. **Understand Closed vs. Open Circulatory Systems**:
- A **closed circulatory system** is one where the blood is contained within vessels, allowing for more efficient transport of nutrients and oxygen.
- An **open circulatory system** is one where the blood is not always contained within vessels and can flow freely in the body cavity.

3. **Analyze Each Option**:
- **A. Bombyx**: This is a genus of insects (silkworms) that belong to the phylum Arthropoda. Insects typically have an open circulatory system. Therefore, Bombyx has an open circulatory system.

- **B. Sepia**: This refers to the common cuttlefish, which is part of the class Cephalopoda within the phylum Mollusca. Cephalopods are known to have a closed circulatory system, which is an exception among mollusks. Therefore, Sepia has a closed circulatory system.

- **C. Balenoglossus**: This organism belongs to the phylum Hemichordata. Hemichordates generally have an open circulatory system. Therefore, Balenoglossus has an open circulatory system.

- **D. Ascidia**: Ascidia, or sea squirts, belong to the phylum Chordata. They are considered primitive chordates and also possess an open circulatory system. Therefore, Ascidia has an open circulatory system.

4. **Conclusion**: After analyzing all the options, the only organism that has a closed blood vascular system is **B. Sepia**.

### Final Answer:
The closed blood vascular system is found in **B. Sepia**.

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