Nematodes are called pseudocoelomates. Why ?

Explanation

### Step-by-Step Solution:

1. **Definition of Nematodes**: Nematodes, commonly known as roundworms, belong to the phylum Nematoda. They are characterized by their elongated, cylindrical bodies and are found in various habitats.

2. **Understanding Coelom**: A coelom is a fluid-filled body cavity that is completely lined by mesoderm tissue. It serves various functions, including providing space for the development of organs and facilitating movement.

3. **Types of Body Cavities**:
- **Coelomates**: Animals with a true coelom, where the body cavity is completely lined by mesoderm (e.g., humans).
...