In Amphioxus, blood circulatory system is :–

Options

A. Closed
B. Without heart
C. Without respiratory pigment
D. All of above

Answer

To answer the question regarding the blood circulatory system in Amphioxus, we can break down the information step by step:

### Step-by-Step Solution:

1. **Understanding Amphioxus**: Amphioxus, also known as lancelets, are small, fish-like marine animals that belong to the subphylum Cephalochordata. They are significant in studying the evolutionary aspects of vertebrates.

2. **Type of Circulatory System**: The circulatory system in Amphioxus is classified as a **closed circulatory system**. This means that the blood circulates within blood vessels and does not flow freely in the body cavity.

3. **Absence of Heart**: Unlike many other organisms, Amphioxus does not possess a heart. Instead, the blood is moved through the vessels by the contraction of the vessel walls.

4. **Lack of Respiratory Pigments**: Amphioxus does not have respiratory pigments like hemoglobin in their blood. This means that oxygen is not transported in the same way as in organisms with hemoglobin.

5. **Conclusion**: Based on the above points, we can conclude that the blood circulatory system in Amphioxus is closed, without a heart, and lacks respiratory pigments.

### Final Answer:
In Amphioxus, the blood circulatory system is closed, without a heart, and without respiratory pigments.

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