It’s magnesium magnesium has 3 levels and carbon only has two levels
Mercury, Venus, Earth, and Mars are all known as terrestrial planets I believe.
The correct answer is option Observations can be made from outside the "system".
The study of the plate tectonics allows the observation of the movement of the plate tectonics. These observation can be study to determine the pattern of the movement from outside the plate tectonics system and the event occurring due to plate tectonics can be predicted.
President Lincoln said the "insurgents" wanted to fight because they wanted to extend and perpetuate slavery. At the end of the Civil War, the "insurgents" did not get their wish. The correct answer is B.