…………... is filled with endolymph while …………... is filled with perilymph.

Explanation

**Step-by-Step Solution:**

1. **Identify the Fluids:**
- Endolymph is a fluid that is rich in potassium and low in sodium and calcium.
- Perilymph is a fluid that is rich in sodium and low in potassium and calcium.

2. **Identify the Structures:**
- The structure that is filled with endolymph is the **Scala Media**.
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