Answer:
I know its weird, but: object sexuality
Explanation:
The main purpose of a keyword search is to D. find only those results that relate to your topic. It's quite obvious really. If you place a keyword in a search engine, the goal would be to find sources that relate to the word you typed in. Thus, your answer is D.
3) add information that further explains or defines the main idea.
Extension mean to add on to, so 3) is the correct answer.
