Answer:
What is born on the ground but floats to the sky, to be returned back again from the clouds up high?
You use it between your head and your toes, the more it works the thinner it grows. What is it?
What goes up let's of a load and come back down
Long and thin, red within, with a nail at the end.
If it is absolute, it will corrupt absolutely.
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?