The diagram shows a Euglena, a single-celled organism.

The diagram shows a Euglena, a single-celled organism.

• Part I points to the flagellum, used for locomotion.
• Part II points to the small, dark spot near the base of the flagellum. This structure is the eyespot (or stigma), which is light-sensitive and helps the Euglena detect light.
• Part III points to the star-shaped structure, which is the contractile vacuole, responsible for osmoregulation.
• Part IV points to the main body of the cell, likely indicating the cytoplasm or general cell structure.

Based on the typical anatomy of a Euglena:
The part labeled II is the eyespot.

The correct option is B.

B) eyespot