In an expository essay, the title should clearly indicate the purpose of the essay and give the reader a preview of the main topic being discussed. Some suitable titles for an expository essay could be:
1. "Exploring the Impact of Climate Change on Marine Ecosystems"
2. "Unraveling the Science Behind Vaccinations: Separating Fact from Fiction"
3. "Analyzing the Effects of Social Media on Mental Health"
4. "Understanding the Importance of Financial Literacy in Today's Society"
5. "The Role of Technology in Shaping Modern Education"
These titles are specific, informative, and indicative of the analytical and explanatory nature of an expository essay.