Rick’s class plans to study the effect of eating different breakfast foods on grades in morning classes. Students in the class will be the test subjects for the investigation. Which of the following would most likely make the results of the experiment invalid? Half of the students ride the bus to school, and half ride in cars. Some students eat breakfast two hours before other students do. Some students miss school during the investigation due to illness. All students in the investigation have morning classes in the same subjects.

(courts and civil liberties 04.04 hc) "the right of citizens of the united states, who are eighteen years of age or older, to vote shall not be denied or abridged by the united states or by any state on account of age." which of the following reflects the source and impact of this quote? (5 points) the 19th amendment protects the right to vote for all legal adults. before this amendment, voters had to not only be an adult but also serve in the armed forces and be a high school graduate before they could vote. the 26th amendment protects the right to vote for all legal adults. before this amendment, young adults could be in college or even serving the military in combat but not be eligible to choose their leaders for a few years. the 19th amendment prevents states from allowing minors to vote. before this amendment, widespread voter fraud was an issue throughout the states, as parents would vote multiple times using their children's names. the 26th amendment prevents states from allowing minors to vote. before this amendment, candidates directed their campaigns at children and teens through cartoons rather than focusing on real political issues.