padi IDC theory – SCUBA equipment

Q3
A hydrostatic test needs to be performed after_______
b)   A tank being exposed to high temperatures

Q4
The second stage of a regulator works as follows:
a)    A piston or diaphragm opens a valve releasing air from the tank
b)   A diaphragm opens a valve releasing air from the first stage
c)    Reduces the surrounding pressure
d)   Releases air continuously