In an informative/explanatory article, about summer activities for teenagers, the following concept would be used to inform the reader:
The locations of summer camps.
An informative essay aims to give the reader some insight about a specific topic. The location of summer camps gives some information pertaining the topic (summer camps), which might interest the reader. However, the importance of staying active does not let the reader know anything about summer camps. The best new summer movies does not relate to summer camps. Finally, the amount of money earned in part time jobs does not give any insight about summer camps.