they do nothing. They are there because you have hair all over your body.
Your question makes no sense. Only human children can be "adopted", root hairs cannot be adopted. Further, root hairs are plural so it should be "their function" not "its function".
Then you won't have any hairs there.
1
Rhizoids are unicellular absorbtive hairs and their function is absorption
when the hairs stand up on a dogs back they are known as Hackles
I am not sure on what basis you distinguish between natural and unnatural methods of hair removal. You can shave hair off of a hand (or any location on the body) or you can pluck hairs with tweezers, which is much slower, but leaves no stubble behind. Of course, the hair will grow back. If you don't want it to grow back there is electrolysis, but presumably you consider that to be unnatural.
It works as a filter for particles in the air.
The function of root hairs is to absorb water and nutrients from the soil. If the root hairs have a cuticle covering, it will prevent the free absorption of water and nutrients from the soil.
the function known as elongation
You can pluck the little hairs
yes
allows the exit of hairs through the epidermal surface