Haemocoelomic system is the circulatory system of

Options

A. Polynoe
B. Aphrodite
C. Leech
D. None of these

Answer

### Step-by-Step Text Solution:

1. **Definition of Hemocoelomic System**: The hemocoelomic system is a type of circulatory system found in certain invertebrates. It is characterized by the presence of a hemocoel, which is a body cavity filled with a fluid called hemolymph.

2. **Understanding Hemolymph**: Hemolymph is the fluid that circulates within the hemocoel. Unlike blood in vertebrates, hemolymph is generally colorless or has a yellowish tint and does not contain hemoglobin. It serves a similar function to blood, transporting nutrients, waste products, and gases throughout the organism.

3. **Organisms with Hemocoelomic System**: The hemocoelomic system is primarily found in invertebrates, particularly in arthropods (like insects, arachnids, and crustaceans) and some mollusks. These organisms do not have a closed circulatory system like vertebrates.

4. **Function of the Hemocoelomic System**: The hemocoelomic system allows for the distribution of nutrients and the removal of waste products. It also plays a role in the immune response of the organism, as hemolymph contains immune cells.

5. **Conclusion**: In summary, the hemocoelomic system is the circulatory system of certain invertebrates, characterized by the presence of hemolymph in a hemocoel.