Aparagraph is defined as a group of sentences that center on a

- "the basic difference between keywords and subjects is that subjects (or "subject headings") have been predetermined, while keywords have not. a keyword is an easy place to start because you can use any word that seems to fit your search; this is called "natural language" searching."

this is what i put and it was correct

it's a way for authors to communicate with reader in this time period. books from the past can teach us about life.