How does a representative democracy differ from an oligarchy?

The representative democracy represents the whole democracy and the power is in hands of the representatives chosen by the democracy.The oligarchy has the power vested in hands of small group of people who are not represented by the people but by the power either being money or being military.Representative democracy holds the power to discontinue the representative from representation.In oligarchy no such right is exercised and the power may remain forever.

i didn’t understand your question but archipelagos are groups of island hope this

Answerequatorial guinea,gabon, and western sahara;