Which is not a technique for better understanding a subject

Read this excerpt from the declaration of independence

Which of the following best describes how the majority of content decisions are made by the media?

In paragraph 5, president obama remarks: “you know, when trayvon martin was first shot i said that this could have been my son. another way of saying that is trayvon martin could have been me 35 years ago.” how does president obama use rhetoric in this quote to contribute to the overall meaning of his speech?