Answer:
Two in a whole and four in a pair. Six in a trio you see. Eight's a quartet but what you must get is the name that fits just one of me.
I pass before the sun, yet make no shadow. I'm all around you, but you cannot see me. What am I?
I go through a door but never go in, and never come out. What am I?
I walk on 4 legs in the morning, 2 legs at noon, and 3 legs at night. What am I?
I am what no man ever yet did see, which never was, but always is to be. What am I?
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?