ElementaryUnit is an intrusive macOS application that may be installed without the user's knowledge. Often, software of this sort might be spread through fake updaters/installers, deceptive advertisements, or via opt-in offers found in software bundles. The latter method is very popular when it comes to spreading Potentially Unwanted Programs (PUPs) for macOS, so users must be extra careful when installing unknown software that might include opt-in offers. Pay close attention to the instructions, and always decline extra offers for software or subscriptions.
The good news is that failing to prevent ElementaryUnit from being installed will not result in very negative consequences. This application is not threatening, but it may be difficult to remove. Its presence on your computer is likely to be accompanied by unexpected changes in your Web browser's behavior.
ElementaryUnit is known to promote shady search engines by setting them up as the Web browser's default search page or new tab page. It also may trigger redirects to unknown websites. Last but not least, removing it manually may not be easy since some users report that it was installed as both a standalone application and as a browser add-on.
The best way to dispose of ElementaryUnit and revert the changes it brought is to run a reliable macOS security scanner. We also would advise you to consider adding an anti-virus software as an extra layer of protection considering the rapidly increasing number of threats targeting macOS devices exclusively.