What is the difference between keyword and subject heading searching?
Select one:
1. A keyword can be found in any part of the description of the article including the author’s name; a subject heading describes an important concept in the article.
2. They are the same thing.
3. A keyword can only be found in the title of an article; a subject heading is found only in the abstract of an article.
4. A keyword describes an important concept in the article; a subject heading can be found in any part of the description of the article.