Go to google and look up how are air bags changing for number 2. and look up new airbag technologies in google and rewrite that in a few paragraphs for number 3.
The best word to fill the blank is "saturated". Hydrocarbons with only single bonds are saturated. These hydrocarbons are the deemed to be the simplest class. They are called saturated because each carbon is bonded to as many hydrogen as possible.
Protons and neutrons i think , sorry if i’m wrong.
