Give the difference between open and closed circulation.

Explanation

### Step-by-Step Solution:

1. **Definition of Circulatory Systems**:
- **Open Circulatory System**: A type of circulatory system where the blood (or haemolymph) is not confined to blood vessels and bathes the organs directly.
- **Closed Circulatory System**: A type of circulatory system where blood is enclosed within vessels and is circulated through these vessels.

2. **Presence of Vessels**:
- **Open Circulatory System**: Lacks blood vessels; instead, the blood (haemolymph) flows freely in the body cavity.
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