In symbiotic relationship between fig tree and wasp, the wasp uses fig fruit for `ul(x)` and developing seeds for `ul(y)`. In turn favours `ul(z)`.

Answer

To solve the question regarding the symbiotic relationship between the fig tree and the wasp, we need to identify what X, Y, and Z represent in this context.

### Step-by-Step Solution:

1. **Understanding the Relationship**:
- The relationship between the fig tree and the wasp is a mutualistic symbiosis. This means both the fig tree and the wasp benefit from their interaction.

2. **Identifying X**:
- The wasp uses the fig fruit for laying eggs. This process is known as oviposition. Therefore, we can fill in:
- **X = Oviposition**

3. **Identifying Y**:
- The wasp also uses the developing seeds inside the fig for nourishment. The larvae that hatch from the eggs laid in the fig will feed on these developing seeds. Thus, we can fill in:
- **Y = Nourishing its larva**

4. **Identifying Z**:
- In turn, the activity of the wasp leads to the pollination of the fig tree. As the wasp lays eggs and feeds its larvae, it also facilitates the pollination process of the fig tree. Therefore, we can fill in:
- **Z = Pollination**

### Final Answers:
- **X = Oviposition**
- **Y = Nourishing its larva**
- **Z = Pollination**