Air passages such as your trachea (windpipe), which may contain air your body can't use, are known as: 1: Brachia. 2: Bronchials. 3: Dead air spaces. 4: Restricted orifices. {Ans: Correct Answer: Dead air spaces. Explanation: Air passages such as your trachea (windpipe), which may contain air your body can't use, are known as dead air spaces.}Among the easiest ways to don a heavy weight belt, at the surface or under water, is to: 1: Pass it under your feet. 2: Roll into it. 3: Back into it. 4: None of the above. {Ans: Correct Answer: Roll into it. Explanation: Among the easiest ways to don a heavy weight belt, at the surface or under water, is to roll into it.}Which of the following is/are important features of a weight system? 1: The ability to quickly and reliably jettison at least enough weight to make the wearer positively buoyant at the surface or at depth. 2: The ability to carry a minimum of at least 25 kg/55 lbs of weight. 3: The ability to easily adjust the amount of weight used. 4: Both the first and third answers are correct. {Ans: Both the first and third answers