A. Abrasion
Reason - cause by scraps on rough surface which breaks skin on outer layer.
See attached image for most common formula of sulfuric acid.
Answer:
I think it just all exists at once, if it never is created or destroyed. It must have just appeared at the same time at some point. It doesn't exactly come from anywhere, but that's my opinion. There might be another scientific answer out there, but that's what i think. I hope this helps.
Explanation:
