Waste material is discharged to outer body surface, directly by

Options

A. Pharygeal nephridia
B. Septal nephridia
C. Intergumentary nephridia
D. All of these

Explanation

**Step-by-Step Solution:**

1. **Understanding Nephridia**: Nephridia are excretory organs found in earthworms and other members of the phylum Annelida. They are responsible for the excretion of waste materials and help in osmoregulation.

2. **Types of Nephridia**: There are three types of nephridia based on their location:
- **Pharyngeal Nephridia**: Located in the 4th, 5th, and 6th segments of the earthworm. They discharge waste into the buccal cavity and pharynx, from where it is expelled through the anus.
- **Septal Nephridia**: Present from the 15th segment onward. They discharge waste products into the lumen of the intestine.
- **Integumentary Nephridia**: Present in all segments except the first two. They discharge waste directly to the outer body surface through structures called nephrostomes.

3. **Analyzing the Question**: The question asks which type of nephridia discharges waste material directly to the outer body surface.
- Pharyngeal nephridia do not discharge waste directly to the outer surface; they release it into the buccal cavity.
- Septal nephridia also do not discharge waste directly to the outer surface; they release it into the intestine.
- Integumentary nephridia are the only type that discharges waste directly to the outer body surface.

4. **Conclusion**: The correct answer to the question is "Integumentary Nephridia," as they are responsible for discharging waste directly to the outer body surface.

**Final Answer**: Integumentary nephridia.

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