The question is a bit confusing. Since there is only one state and one river named Mississippi, I can't think of a use for a plural form of the noun.
If, for some reason you would have a use for a plural form, it would be two Mississippis. The plural possessive form would be the two Mississippis' border.
The plural form is valleys. The plural possessive is valleys'.
The plural form is replies. The plural possessive is replies'.
No, it is singular, the possessive form of it is its. The plural form of it is they or them, and the possessive form is their.To answer the question directly: there is no such word as ITS'.
The plural form is branches. The plural possessive is branches'.
The plural form is ravines. The plural possessive is ravines'.
The singular possessive form is heart's; the plural possessive form is hearts'.
The plural form is valleys. The plural possessive is valleys'.
The plural form is replies. The plural possessive is replies'.
The plural form is founders. The plural possessive is founders'.
No, it is singular, the possessive form of it is its. The plural form of it is they or them, and the possessive form is their.To answer the question directly: there is no such word as ITS'.
The plural form is branches. The plural possessive is branches'.
The plural possessive form of "mass" is "masses'".
The plural possessive is experiments'.
The plural form is ravines. The plural possessive is ravines'.
The plural form of the noun mouthful is mouthfuls.The plural possessive form is mouthfuls'.
The plural form of the noun kiss is kisses.The plural possessive form is kisses'.
The plural form for the noun wish is wishes; the plural possessive form is wishes'.