Final answer:
Possessive nouns are indicated by adding an apostrophe and -s ('s) to the singular form of the word. Contractions use an apostrophe to indicate omitted letters.
Step-by-step explanation:
Possessive nouns are indicated by adding an apostrophe and -s (['s]) to the singular form of the word. For example, 'the owner's insurance' and 'the waitress's coat' show possession. When a plural noun ends in -s, the apostrophe is placed after the final -s, as in 'American households' incomes.' Contractions, on the other hand, use an apostrophe to indicate omitted letters, such as 'can't' and 'it's'.