<em>Destructive interference</em> is when there are two waves <u>with the same frequency</u>, and the peaks of one wave (the highest points) line up with the valleys (the lowest points) of the second one.
Constructive interference would cause the sound to be louder.
Absorption and reflection are interactions that would not take into account the fact that the headphones produce sounds.
The symbol for gold is Au which only has one capital letter. This means that there is only one thing that makes up gold which would make it an element.