Answer:
I come without being fetched at night hides away as soon as daylight strikes. Although I may look small I am much mightier than what you can imagine.
I transfer oxygen from the atmosphere to your blood
I have skin, more eyes than one. I can be very nice when I am done. What am I?
You can see it everyday, but cannot touch it at will. What is it?
With a halo of water and a tongue of wood, stone as skin long I stood. What am I?
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?