Which of the following tools is NOT used for research purposes?

Google Docs is a word processing tool primarily designed for creating and editing documents collaboratively. It does not serve a research purpose in the same way the other tools do. Researchers might use Google Scholar to find scholarly articles, Google Trends to analyze the popularity of search terms over time, or the Explore Tool to gain insights and discover data related to various topics. Each of these other options provides functionalities to facilitate research and help users gather, analyze, and present information, distinguishing them from Google Docs, which is primarily focused on document preparation and editing rather than research.