Organelles are the subcellular compartments present in the eukaryotes (such as plants and animal cells). They serve specialised functions to the cell. For example- Mitochondria is used to generate large amount of energy in the form of ATP.
Organelles are absent in the prokaryotes such as organisms belonging to the domain Eubacteria like E.coli.
Thus, 'presence of organelle' is the key feature that helped Sally to rule out the kingdom Eubacteria.
