ROI is Ireland aka Southern Ireland which is separated from NI aka Northern Ireland which is a part of the U.K. aka The United Kingdom of Great Britian and Northern Ireland which also includes England, Scotland and Wales. Great Britain is technically the land name of The United Kingdom of Great Britain and Northern Ireland. Each country within the “states” of U.K. have it’s own government and rules blah blah blah Is that ok for you or did my geography GCSE fail poor old me or would you like me to give you further knowledge of my own country where I don’t just live but was born and raised with parents from different parts of the U.K. ? I also might be able to teach you a few things about Volcanoes too from my GCSE geography days if you’d like!?People who live in the uk really need to develop at least a basic understanding of ROI, NI, Britain and the UK.