What is the question here?
Chronological order is a sequence of events, while compare and contrast puts two topics together and shows the differences and similarities.
The underlined word <em>unique </em>is used as C. predicate adjective in the sentence.
A predicate adjective is the adjective following a copulating/linking verb.
The linking verb here is <em>is, </em>and the predicate adjective is therefore the adjective following it, which is <em>unique. </em>
