Given the sequence below, determine whether it is Arithmetic or not, if not, given a reason. 1. 2,4,6,8, ... 2. 3, 6, 10, 15, ... 3. -3, -1, 1, 3, ... 4. 5, 10, 20, 40, ... 5. 10, 6, 2, -2, ...​