Answer:
Independent: electronics in room
Dependent: hours of sleep
Control: school nights, night routine, lighting of room, the time the person decides to go to bed
Confounding: the person(?? not entirely sure on this one)
Red blood cell antibodies may show up in your blood if you are exposed to red blood cells other than your own. Antibody serology tests check for the presence or level of specific antibodies in the blood.
Answer: 80-90%
Explanation: "Cigarette smoking is the number one risk factor for lung cancer. In the United States, cigarette smoking is linked to about 80% to 90% of lung cancer deaths. Using other tobacco products such as cigars or pipes also increases the risk for lung cancer." - cdc.gov