Which relationship is possible when two tables share the same primary key? one-to-one one-to-many many-to-one many-to-many

Many-to-one relationships is possible when two tables share the same primary key it is because one entity contains values that refer to another entity that has unique values. It often enforced by primary key relationships, and the relationships typically are between fact and dimension tables and between levels in a hierarchy.

Idon't have a single clue tbfh