Arrange from highest to lowest in order of decresing mass:

1 Gg, 100 g, 1 kg, 50 cg, 1 cg, 1 dg, 50 million ng

From the units of the measurements given, the one with the largest mass would the one with units Giga-grams while the smallest would be the one with units of nano-grams. However, this depends on the numerical values given. Therefore, the correct order would be:

1 Gg, 1 kg, 100 g, 50 cg, 50 million ng, 1 dg, 1 cg