Lungs lie in the thoracic cavity separated by .................. from the abdominal cavity.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the anatomical structure that separates the lungs in the thoracic cavity from the abdominal cavity.

2. **Identifying the Location of the Lungs**: The lungs are located in the thoracic cavity, which is the upper part of the torso, enclosed by the ribcage, vertebral column, and sternum.

3. **Recognizing the Structures Involved**: The thoracic cavity is bounded by various structures:
- Dorsally (at the back) by the vertebral column (spine).
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