Which of the following describes passing by reference?

The measure of the angles supplement is 30 more than four times that of its complement. find the measure of the angle described

Earth's atmosphere is unique among the planets and is able to support life because it contains a large amount of a) oxygen b) helium c) methane d) carbon dioxide

Case # 51173878 weighs 814 pounds; case # 51173981 weighs 803 pounds; case # 51174058 weighs 817 pounds; case 51174178 weighs 815 pounds; case # 51174248 weighs 817 pounds; case # 51174495 weighs 781 pounds; case # 51174577 weighs 828 pounds. what are the case #'s of the two cases that weigh the same amount?