Coelom is lined by :-

Options

A. Ectoderm
B. Mesoderm
C. Endoderm
D. Mesogloea

Answer

To answer the question "Coelom is lined by:", we need to understand the structure of the coelom and the germ layers involved in its formation. Here’s a step-by-step solution:

### Step 1: Understand the Definition of Coelom
- The coelom is a fluid-filled body cavity found in many animals, which is lined by mesoderm. It serves as a space for the development and organization of internal organs.

### Step 2: Identify the Germ Layers
- In animal development, there are three primary germ layers:
1. **Ectoderm**: The outermost layer, which forms the skin and nervous system.
2. **Mesoderm**: The middle layer, which gives rise to muscles, bones, and the coelom.
3. **Endoderm**: The innermost layer, which forms the lining of the digestive tract and associated organs.

### Step 3: Determine Which Layer Lines the Coelom
- The coelom is specifically lined by the mesoderm. This layer is responsible for forming the lining of the coelomic cavity and is crucial for the development of various internal structures.

### Step 4: Eliminate Incorrect Options
- **Ectoderm**: Incorrect, as it does not line the coelom.
- **Endoderm**: Incorrect, as it is involved in forming the gut lining, not the coelom.
- **Mesogloia**: Incorrect, as it is a gelatinous substance found in some organisms (like cnidarians) but not a germ layer.

### Conclusion
- The correct answer to the question "Coelom is lined by:" is **mesoderm**.

### Final Answer
- **B. Mesoderm**