What is a haemocoel? ls this an open or closed form of circulation?

Explanation

### Step-by-Step Solution:

1. **Definition of Haemocoel**:
- Haemocoel is defined as a body cavity that is filled with a fluid known as hemolymph. This cavity is found in certain invertebrates, particularly in arthropods.

2. **Composition of Hemolymph**:
- Hemolymph, the fluid within the haemocoel, contains various components such as ions, hormones, and excretory wastes. This composition allows it to perform multiple functions, including nutrient transport and waste removal.

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