To arrange in descending order or greatest to least, we will first convert all the values in same unit.
Lets convert all the values in kg
1 lb = 0.45 kg
2 lb = kg
1 g = 0.001 kg
891 g = kg
1 T = 907.185 kg
0.02 T = kg
Hence all values in kg becomes = 0.90 kg , 0.891 kg , 1 kg , 18.14 kg
So in descending order the values become
0.02T, 1 kg, 2 lb, 891 g