Read the glossary entry for the term disturbance. disturbance \di'-stur-bəns\ n 1. an interruption of flow 2. an altering of order or position 3. an upset of natural balance 4. a destruction of tranquility or calm

Which definition most closely matches the way the word disturbance is used in paragraph 6?
Paragraph 6: Before manufacturers built the airplanes, the designs were developed,
tested, and refined at the Langley Memorial Aeronautical Laboratory,
which was where the NACA had first begun its operations, in 1917.
The engineers created wind tunnels to simulate, or imitate, different
conditions a plane could encounter when flying. This helped the
engineers to test airplane parts as well as whole aircraft, examining
them for any problems, like air disturbance and uneven wing
geometry.