Answer:
The answer is: she was emphasizing scentific evidence that supports her speech.
Explanation:
when delivering a speech, people use persuasive strategies that help them support the argument they are making. In this case, Ariana was demonstrating relevance of the negative effects of sleep by emphasizing existing scientific evidence; she mentions that it has been proven that there is a link between a lack of sleep during school week and poor academic performance. By using this data as a persuasive tool, she can make a stronger speech because it is based on objective information rather than on a subjective belief.