The noun choir is a singular noun; the plural form is choirs.
Example: The choirs of three local churches will be performing at the ceremony.
choirs'
Choir's is the possessive form of the noun.
The singular possessive form is heart's; the plural possessive form is hearts'.
The plural form is homes; the plural possessive is homes'.
The plural of rose is roses. The plural possessive is roses'.
The plural possessive is regions'.
The plural form of the noun deaconess is deaconesses.The plural possessive form is deaconesses'.Example: The deaconesses' daughters are in the choir.
The possessive form of choir is choir's.
Choir's is the possessive form of the noun.
The plural is relatives. The plural possessive is relatives'.
The plural is lads. The plural possessive is lads'.
The plural form is Mexicans. The plural possessive is Mexicans'.
The plural possessive of stepsister is stepsisters'.
The plural form is suffixes. The plural possessive is suffixes'.
The plural form is echoes. The plural possessive is echoes'.
Coaster's is singular possessive. The plural is coasters, the plural possessive is coasters'.
The plural possessive is pals'.
Studies' is the plural possessive of study.