In soil taxonomy, Great group is defined largely on the basis of

Solution (By Examveda Team)

In soil taxonomy, the Great group is defined largely based on the Diagnostic surface horizon.
Soil taxonomy is a morphogenetic soil classification system using diagnostic horizons, soil moisture or temperature regimes, and features to infer pathways of soil genesis and formation. It employs a unique mnemonic system based on Greek, Latin or other root words for assigning names to taxonomic classes.