Choose the ODD one out of the following terms given and name the CATEGORY to which the others belong :
Aqueous humour, Vitreous humour, Iris, Central canal

Explanation

To solve the question, we need to analyze each of the given terms: Aqueous humour, Vitreous humour, Iris, and Central canal.

1. **Understanding the Terms**:
- **Aqueous Humour**: This is a clear fluid found in the front part of the eye, specifically in the anterior chamber. It helps maintain intraocular pressure and provides nutrients to the eye.
- **Vitreous Humour**: This is a gel-like substance located in the back part of the eye, known as the vitreous chamber. It helps maintain the shape of the eye and provides support to the retina.
- **Iris**: This is the colored part of the eye that surrounds the pupil. It regulates the amount of light that enters the eye by adjusting the size of the pupil.
- **Central Canal**: This is a part of the spinal cord that contains cerebrospinal fluid and is not related to the eye.

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