The thick part of the choroid layer forms

Options

A. cornea
B. iris
C. ciliary body
D. ganglion

Answer

To solve the question about which structure is formed by the thick part of the choroid layer, we can follow these steps:

### Step 1: Understand the Layers of the Eye
The eye consists of three main layers:
1. **Sclera** - the outermost layer.
2. **Choroid** - the middle layer.
3. **Retina** - the innermost layer.

### Step 2: Identify the Role of the Choroid Layer
The choroid layer is responsible for providing blood supply to the eye and contains a network of blood vessels. It is thinner at the posterior part and thicker at the anterior part.

### Step 3: Determine the Thick Part of the Choroid Layer
The thick part of the choroid layer forms the **ciliary body**. The ciliary body is involved in the accommodation of the lens and helps control the shape of the lens for focusing.

### Step 4: Analyze the Options Given
- **Cornea**: This is formed from the outer layer (sclera) and is not part of the choroid.
- **Iris**: This is the colored part of the eye but is not formed from the choroid.
- **Ciliary Body**: This is the correct answer as it is the thickened part of the choroid.
- **Ganglion**: This refers to ganglion cells in the retina, which are not related to the choroid layer.

### Conclusion
The thick part of the choroid layer forms the **ciliary body**.

### Final Answer
**Ciliary Body**

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