in 1-2 sentences explain how to use an apostrophe to show possession for singular and plural nouns and to form contractions

To show possession, use an apostrophe followed by an "s" for singular nouns (e.g., the cat's toy) and an apostrophe after the "s" for plural nouns (e.g., the cats' toys); to form contractions, use an apostrophe to replace missing letters (e.g., it's for it is).