Im just some random dude so i think its maybe assisting them
I would say hair, since puberty is when young teens start shaving their armpit and leg hair.
Yes this is very true most people’s don’t think before they act which is acting on impulse and they don’t realize what they did till after
You do it before a lab so as to prevent contamination of the materials. You might have things on your hands that might contaminate the experiment and the research. You do it after because you don't want to have things from your experiments on your hands because that can be extremely dangerous.
Drink a lot of water and keep being hydrated.