Explanation:

- Insects have a unique system for gas exchange called the Tracheae.

- These are tiny tubes that extend throughout the insect's body, allowing air to reach internal tissues directly.

- Correct Answer: Tracheae

- Gills are used by aquatic animals like fish for gas exchange, not insects.

- The Diaphragm is a muscle found in mammals, aiding in breathing, but not present in insects.

- Spiracles are openings on the insect’s body surface that lead to the tracheal system, allowing air to enter.