Independent clauses are sequences of words which contain a subject and a predicate and which can stand on their own as a complete sentence and thought. They are found in simple sentences, compound sentences (joined by a semicolon, or a comma with a coordinating conjunction), as well as in complex and compound-complex sentences, which also possess dependent or subordinate clauses.
They mention the story of Rapunzel but not everybody knows what happens during her journey. It's quite obvious how difficult Hansel and Gretel's situation is, but we know nothing of Rapunzel.