Parent rocks.
( I got it wrong when I put Inorganic materials)
The most suitable option for the first question is definitely <span>stratus clouds which usually stratch over the sky creating overcasts.
The next one should be </span><span>nimbus, as they dark and usually help to predict the storm.
And the last one </span>cumulonimbus that point on thunderstorms and so on.
Answer:
A diving regulator is a pressure regulator that reduces the pressure of gas in the tank and deliver it to the diver so that he/she can breathe easily. It must pass the controlled laboratory testing and must have a second adjustment knob to ensure ease of breathing. Modern regulators are precision made and designed to work under demanding conditions. 1st stage and 2nd stage, diaphragm and piston, exhaust valve and purge button are types of diving regulators.
