GRAMMAR WARS! YAAAY!
GRAMMAR WARS! YAAAY! (Immmortal inner 5th Grade Schoolmarm dons armor and broadsword.)
Zombie: In English, the possessive is indicated by having an apostrophe-s after the noun
I don't think "its"-possessive is counted in that noun-possessive apostrophe rule (if exceptionally) because "its" is a pronoun like its cousins "his" and "hers" and "ours" and "theirs" - which, obviously, do not take apostrophes. Still doesn't necessarily make sense, but has some consistency.