When a plural word ending in s needs to be possessive, where does the apostrophe go?

When a plural word ending in "s" needs to be possessive, the general rule is to add an apostrophe after the "s". For example:

- The cats' toys (The toys belong to multiple cats).
- The boys' bicycles (The bicycles belong to multiple boys).
However, there are some exceptions. If the plural word does not have a distinct plural form, then you add an apostrophe followed by an "s". For example:
- The species's habitat (The habitat belongs to the species).
- The corps's decision (The decision belongs to the corps).