Complex sentence: A flagellum (plural: "flagella") is a tail-like projection that protrudes from the cell body of certain prokaryotic and eukaryotic cells, and plays the dual role of locomotion and sense organ, being sensitive to chemicals and temperatures outside the cell.
Split into simpler sentences: A flagellum (plural: "flagella") is a tail-like projection that protrudes from the cell body of certain prokaryotic and eukaryotic cells. The canonical role of the flagellum is locomotion but it also often has function as a sensory organelle, being sensitive to chemicals and temperatures outside the cell.