Which of the following is NOT a mobile system?

Tactical ventilation reduces fire damage in structures and limits water damage because it:

A. focuses on the use of foam to fight interior fires. B. allows for the use of fire streams with lower pressures. C. increases speed with which interior fires can be extinguished. D. allows salvage operations to begin simultaneously with fire attack.

When sound waves hit the ____________________, they cause a vibration that travels through the middle and inner ear chambers

Fill in the blank(s) with correct word