<span>One of the themes in "The Tempest" is that of justice and the reality or falseness of it.
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Assuming the italicized clause is <em>Since its establishment, </em>the correct answer here is elliptical clause.
Elliptical means that a word which would normally be part of a sentence is excluded, usually for stylistic reasons. Here, the verb is missing, which is why it is elliptical. The question is oddly formulated too - given that there is no verb here, it cannot be a clause, but rather a phrase, but since there is no such option here, then the correct answer is elliptical clause.
In general you want to be a bit more concise in forming a thesis statement. Usually you should shoot for between 1 and 2 sentences summarizing your argument in a concise way so that it is easily understandable to the reader. I would take what you have written and look for your main argument and try and put that in 1 to 2 sentences.
Answer:
the Mediterranean Sea and the North Atlantic Ocean