Final answer:
The flagellum in Euglena is a long, whip-like structure attached at one end of the cell that, along with a flexible pellicle, aids in its locomotion
Step-by-step explanation:
The flagellum in Euglena appears as a long, whip-like structure which is responsible for the cell's locomotion. Euglena species possess two flagella, with one being notably longer than the other. These flagella are anchored at one end of the Euglena within a small reservoir. In addition to flagellar movement, Euglena can move by altering their shape, a process known as euglenoid movement. The pellicle, a flexible protein layer beneath the cell membrane, provides structural support and enables this shape change. When illuminated, photosynthetic Euglena species utilize chloroplasts to harness light energy, but they can also absorb nutrients from their surroundings in the dark.