Aboard a research station, Emek and Luna had to choose a planet for their next observation mission. Sensors recorded temperatures at four times during the day. Planet A measured 18, 22, 19, and 21 degrees Celsius. Planet B measured 12, 20, 25, and 17 degrees Celsius. Planet C measured 16, 18, 17, and 19 degrees Celsius. Emek and Luna plotted each set of measurements on a line graph. They compared how much the lines rose and fell. Planet B's graph showed large changes, while Planet A's temperatures varied less. Planet C had the smallest change, staying between 16 and 19 degrees Celsius. Since more stable temperatures would make observations easier, Emek and Luna chose Planet C. They entered their destination into the station computer and prepared for the mission.