The noun "Beatles" is a proper noun, the name of a group of British singers/songwritiers. A proper noun is always capitalized.
The possessive form of the plural, proper noun Beatles is Beatles'.
The apostrophe following the ending s indicates possession.
Example: The Beatles' songs are still very popular.
The plural form of the other type of beetle, a word for a type of insect, is beetles.
The plural possessive form is beetles'.
Example: The beetles' colors are green and brown.
The plural form for the noun composer is composers; the plural possessive is composers'.
Pianists is plural The possessive is painists'
The plural form of the noun soprano is sopranos.The plural possessive form is sopranos'.Example: The director rehearsed the sopranos' roles with them.
The plural form of the noun singer is singers.The plural possessive form is singers'.example: The singers' voices filled the auditorium.
The possessive form of the plural noun musicians is musicians'.example: The musicians' rehearsal is scheduled for eight.
Singular possessive: secretary's Plural: secretaries Plural possessive: secretaries'
The plural is lads. The plural possessive is lads'.
The plural is relatives. The plural possessive is relatives'.
The plural form is suffixes. The plural possessive is suffixes'.
The plural form is stepsisters. The plural possessive is stepsisters'.
The plural form is Mexicans. The plural possessive is Mexicans'.
The plural form is echoes. The plural possessive is echoes'.
The plural form is inches. The plural possessive is inches'.
Studies' is the plural possessive of study.
The plural possessive is pals'.
Coaster's is singular possessive. The plural is coasters, the plural possessive is coasters'.
The plural possessive of bandit is bandits'.