The ventral surface of mature earthworm can be distin guished from dorsal surface by

Options

A. Absence of middorsal line
B. Presence of clitellum
C. Presence of genital papillae
D. None of these

Answer

To distinguish the ventral surface of a mature earthworm from the dorsal surface, we can follow these steps:

1. **Understand the Orientation**: Recognize that the ventral surface refers to the underside or front part of the earthworm, while the dorsal surface refers to the upper side or back part.

2. **Identify Key Features**:
- The dorsal surface of the earthworm is characterized by a **dark median mid-dorsal line** that runs along its length. This line is absent on the ventral surface.
- The **ventral surface** has **genital openings** that are not present on the dorsal surface.

3. **Examine Additional Structures**:
- The **clitellum**, which is involved in reproduction, is present on both the dorsal and ventral surfaces, so it does not help in distinguishing between the two.
- The **genital papillae**, which are found on the ventral surface, play a role in reproduction and are absent on the dorsal surface.

4. **Evaluate the Options**:
- **Absence of mid-dorsal line**: This is a distinguishing feature of the ventral surface.
- **Presence of clitellum**: This feature does not distinguish between the two surfaces as it is present on both.
- **Presence of genital papillae**: This is also a distinguishing feature of the ventral surface.

5. **Conclusion**: The ventral surface of the mature earthworm can be distinguished from the dorsal surface by the **absence of the mid-dorsal line** and the **presence of genital papillae**.