A supermarket is a building in which you can buy all kinds of alimentary products like bread, meat, fish, vegetables... Nowadays there are becoming very popular because the people who buy there think that it is more comfortable to buy in this big stores than in little ones.
One advantage of this type of shops is that it's easier to buy in them because they are very big and spacious. Buying in supermarkets takes less time than doing it in little shops, because there are more parking places in big ones. But the most important advantage is that supermarkets are very cheap because most of them have their own brands (they can sell their own products cheaper than others that are made by another business or factory.
The main disadvantage, in the case of Menorca, is that supermarkets whose owners are foreign people, usually take the benefits out of the island. Another disadvantage could be that these king of shops make the little ones disappear, giving less workplaces to people. The final disadvantage is that these lack of work can't be compensated by the workplaces that a supermarket gives, and, because of that, lots of people are against these big stores.