Which one of the following function is not done by 'exoskeleton' of cockroach, 

Options

A. It protects body
B. It helps to lose water
C. It provides rigidity
D. It provides site for attachment of muscles

Answer

To determine which function is not performed by the exoskeleton of a cockroach, we can analyze each of the provided options based on the characteristics and functions of the exoskeleton.

### Step-by-Step Solution:

1. **Understand the Exoskeleton**: The exoskeleton is a rigid structure that is located outside the body of certain organisms, including arthropods like cockroaches. It is primarily composed of a substance called chitin.

2. **Identify Functions of the Exoskeleton**:
- **Protection**: The exoskeleton protects the internal organs of the cockroach from physical damage and environmental hazards.
- **Rigidity**: It provides structural support and rigidity to the body, maintaining its shape.
- **Muscle Attachment**: The exoskeleton serves as a site for muscle attachment, allowing for movement and locomotion.

3. **Evaluate Each Option**:
- **Option 1: Protects the body** - This is a function of the exoskeleton. (Correct)
- **Option 2: Helps to lose water** - This is NOT a function of the exoskeleton. In fact, the exoskeleton helps to prevent water loss, making this option incorrect. (Not a function)
- **Option 3: Provides rigidity** - This is a function of the exoskeleton. (Correct)
- **Option 4: Provides site for attachment of muscles** - This is also a function of the exoskeleton. (Correct)

4. **Conclusion**: The function that is NOT performed by the exoskeleton of a cockroach is that it helps to lose water. Instead, it helps to retain water.

### Final Answer:
The function that is not done by the exoskeleton of a cockroach is: **It helps to lose water.**