What is left after a bath sponge disintegrates and dries ?

Options

A. Silk fibres
B. Muscle fibres
C. Spongin fibers
D. Nerve fibres

Answer

To answer the question "What is left after a bath sponge disintegrates and dries?", we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Bath Sponge**:
- A bath sponge, scientifically known as *Euspongia*, belongs to the phylum Porifera and the class Demospongiae. These sponges are primarily marine and are commonly found in the Mediterranean Sea.

2. **Understand the Composition of Bath Sponges**:
- Bath sponges are made up of a skeleton that consists of spongin fibers. Spongin is a type of collagen protein that provides structural support and flexibility to the sponge.

3. **Process of Disintegration and Drying**:
- When bath sponges are harvested, they are disintegrated and dried. This process removes the organic matter and leaves behind the skeletal structure.

4. **Evaluate the Options**:
- **Option 1: Silk Fibers** - These are produced by silkworms and are not related to sponges.
- **Option 2: Muscle Fibers** - These are found in muscle tissue, not in sponges.
- **Option 3: Spongin Fibers** - These are the collagen fibers that form the skeleton of sponges and are what remain after the sponge dries.
- **Option 4: Nerve Fibers** - These are associated with neurons and are not present in sponges.

5. **Conclusion**:
- After analyzing the options, the correct answer is **Option 3: Spongin Fibers**. When a bath sponge disintegrates and dries, the spongin fibers that make up its skeleton are what is left.

### Final Answer:
**Spongin Fibers**

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