The plural possessive is experiments'.
faculties
The plural form of the noun phenomenon is phenomena.The plural possessive form is phenomena's.Example: These phenomena's occurrences are very rare.
The plural form of the noun freshman is freshmen.The plural possessive form is freshmen's.Example: There will be a freshmen's orientation on Friday.
The plural is Ph.Ds or PhDs (people) and the plural possessive is PhDs'.(the abbreviation with a period or periods is normally used after a name)
Coaster's is singular possessive. The plural is coasters, the plural possessive is coasters'.
The correct form is "its" for the possessive form in the plural. "Its" is used for both the singular and plural possessive forms, without an apostrophe.
The plural is briefs. The plural possessive is briefs'.
The plural is lads. The plural possessive is lads'.
The plural is trollies. The plural possessive is trollies'.
The plural is relatives. The plural possessive is relatives'.
The plural is stations. The plural possessive is stations'.
Museum is singular. Museum's is singular possessive. Museums is plural. Museums' is plural possessive.
The singular possessive form is heart's; the plural possessive form is hearts'.
The plural of rose is roses. The plural possessive is roses'.
The plural form is homes; the plural possessive is homes'.
The singular possessive is biker's; the plural possessive is bikers'.