1st) provide your body with first line of defence against infection by being a protective barrier and secreting oil or sebum 2nd) holds the most important sensory receptors in your body, touch...
No. Like chlamydia, trichomoniasis, and HIV, it's spread through bodily fluids.
There's oily/normal/combination/dry/sensitive skin. Google them and see which one you are.
Acne.
Depends on who "they" are!