The correct answer is key ideas or key points. Key ideas are the ideas that are emphasized through repetition. These ideas are repeated because it needs to be emphasized in order to be understood clearly. Repeated ideas may include a word or phrases. In addition, repetition is also used to persuade or convince the readers.
Depending on which idea some literary work carries within itself, it can be emphasized by repetition. Of course, if you are thinking of a specific idea in your issue, then this would be a general answer. However, the main idea is emphasized for easier understanding by the reader, and it also helps in remembering what is emphasized. This is achieved by repeating the same or similar words or phrase in sentences.