Locomotory structure of Leech is/are

Options

A. Parapodia
B. Setae
C. Muscle
D. All of these

Answer

To determine the locomotory structures of a leech, we need to analyze the options provided: paracordia, setae, muscle, or all of these.

### Step 1: Understand what a leech is
Leeches are segmented worms belonging to the class Hirudinea. They are known for their blood-sucking behavior and have specialized structures for locomotion.

**Hint:** Remember that leeches are segmented worms, and their movement is adapted to their environment.

### Step 2: Identify the locomotory structures
1. **Parapodia**: These are paired, lateral extensions found in some annelids, but leeches do not have parapodia. Instead, they move using other structures.

**Hint:** Think about the specific adaptations of leeches compared to other annelids.

2. **Setae**: Leeches possess small bristle-like structures called setae, which help in anchoring and movement. However, they are not as prominent as in other annelids.

**Hint:** Consider how setae might assist in movement and anchoring.

3. **Muscles**: Leeches have both circular and longitudinal muscles that play a crucial role in their locomotion. The contraction of these muscles allows leeches to move by extending and contracting their bodies.

**Hint:** Muscle movement is essential for locomotion in many animals; think about how leeches utilize their muscle structure.

### Step 3: Conclusion
Since leeches utilize setae and muscles (both circular and longitudinal) for locomotion, the correct answer to the question "Locomotory structure of leech is/are" is **all of these**.

**Final Answer:** All of these (paracordia, setae, muscle).

### Summary of Steps:
1. Identify what a leech is and its classification.
2. Analyze each option (parapodia, setae, muscle) for their relevance to leech locomotion.
3. Conclude that leeches use setae and muscles for movement, making the answer "all of these."