Temirа tells her rооmmаte Cаrmella that she recently read that peоple who paint their rooms blue get better grades. Carmella knows that painting their room will be a lot of work. Therefore, she asks Temira where she got her information and what evidence her sources had for their conclusion. She also wonders if there might not be another reason that people with blue rooms have higher grades—for example, maybe smart people prefer the color blue. What skill is Carmella using?