Which of the following structures is correctly matched with its description ?

Options

A. Septal nephridia and pharyngeal nephridia - Both are exonephric
B. Typhlosole - Helps in grinding the soil particles and decaying leaves
C. Sensory system - Possesses light and touch receptors in earthworm
D. Gizzard - Internal median fold present in the dorsal wall of the intestine of earthworm

Explanation

To determine which of the following structures is correctly matched with its description, let's analyze each option step by step:

1. **Septal Nephridia and Pharyngeal Nephridia**:
- Description: Both are exonephric.
- Analysis: Septal nephridia and pharyngeal nephridia are types of excretory structures found in earthworms. However, they are not exonephric; they are actually anteronephric, meaning they excrete waste into the alimentary canal rather than directly into the environment.
- Conclusion: This statement is incorrect.

2. **Typhlosole**:
- Description: Helps in grinding the soil particles and decaying leaves.
- Analysis: The typhlosole is an internal fold of the intestine that increases the surface area for absorption and digestion. It does not grind soil particles or leaves; that function is performed by the gizzard.
- Conclusion: This statement is incorrect.

3. **Sensory System of Earthworm**:
- Description: Possesses light and touch receptors.
- Analysis: The sensory system of earthworms does indeed include receptors for light and touch, which help the organism respond to its environment.
- Conclusion: This statement is correct.

4. **Gizzard**:
- Description: Internal median fold present in the dorsal wall of the intestine of the earthworm.
- Analysis: The gizzard is actually located in the digestive tract, specifically in segment 8, and is responsible for grinding food. It is not an internal fold of the intestine; that description fits the typhlosole.
- Conclusion: This statement is incorrect.

**Final Answer**: The correct structure matched with its description is the third option: the sensory system possesses light and touch receptors in the earthworm.