The plural form of the noun is planets.
The plural possessive is planets'.
Example: The assignment is to diagram all of the planets' orbits.
The plural is stars. The plural possessive is stars'.
The plural possessive of "sun" is "suns'".
pLURAL ; orbits Possessive plural ; Orbits' (NB note the position of the apostrophe).
The plural form of the noun sky is skies.The plural possessive form is skies'.
The plural possessive form of "Zeus" is "Zeuses'."
The possessive form for the noun planet is planet's.
Singular possessive: secretary's Plural: secretaries Plural possessive: secretaries'
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 form is echoes. The plural possessive is echoes'.
The plural form is suffixes. The plural possessive is suffixes'.
The plural form is stepsisters. The plural possessive is stepsisters'.
The plural form is inches. The plural possessive is inches'.
The plural possessive of "Father" is, "Fathers"
Studies' is the plural possessive of study.
The plural possessive of bandit is bandits'.