Skeleton in Pheretima is

Options

A. bony
B. cartilaginous
C. hydrostatic
D. dermal

Answer

### Step-by-Step Solution:

1. **Identify the Organism**: The question refers to the skeleton of Pheretima, which is commonly known as the earthworm.

2. **Phylum Classification**: Earthworms belong to the phylum Annelida. The term "Annelida" is derived from the Latin word "annulus," meaning "little ring," which reflects the segmented body structure of these organisms.

3. **Body Structure**: The body of the earthworm is primarily muscular and is segmented into ring-like structures. Each segment is filled with a liquid, contributing to the overall structure and function of the organism.

4. **Understanding Skeleton Types**: In general, skeletons can be classified into various types: bony, cartilaginous, hydrostatic, and dermal.

5. **Analysis of Skeleton Types in Earthworms**:
- **Bony Skeleton**: Earthworms do not have bones.
- **Cartilaginous Skeleton**: Earthworms lack cartilage as well.
- **Dermal Skeleton**: The skin does not form a skeleton in earthworms.
- **Hydrostatic Skeleton**: The liquid-filled segments provide a hydrostatic skeleton, which allows for movement and support.

6. **Conclusion**: The correct answer is that the skeleton of Pheretima (earthworm) is hydrostatic, as it relies on the liquid within its body segments for structural support.