Why is euglena a dual organism?
Euglena has chloroplast, which is a plant feature. Euglena has a locomotory structure in the form of a flagellum, which is a property or characteristic of an animal.
It can act both, as an autotroph as it contains chlorophyll and heterotroph as it feed on other substances. Also, in the presence of excess organic matter or darkness, it can act as a saprophytic organism. As Euglena shows features of both plants and animals, it is a dual organism.