(modified) possessive pronoun its

[achilles]

I think I made some mistakes in my question, and I'm writing you this again modifying some parts of the earlier question.
I want to ask you about the possessive pronoun "its".
Of course I know "its" is used as a modifier as in "Its biggest problem is that~~~~ . But what I really wonder is if we can use "its" in a sentence like this. "That is its." "Isn't it its?" Can we use "its" in a sentence like other possessive pronouns such as mine, yours, hers, ours, or theirs?
Could you please give me an answer to my inquiry? And if possible, I want to see an exemplary sentence.
Thanks for your kindness.

[raymon0902]

The food is yours? isn't it mine?

"If you didn't learn a foreign language as a child, you will never be fully proficient in its grammar"

[Tdol]

If the thing/animal is clear then it is possible, but it is much less common that the others.