Give scientific reasons: Euglena is also called a plant-animal.

(N/A) $1$. $Euglena$ is considered a taxonomic puzzle because it exhibits both plant-like and animal-like characteristics.
$2$. The absence of a rigid cell wall is an animal-like feature,while the presence of chloroplasts for photosynthesis is a plant-like characteristic.
$3$. $Euglena$ exhibits mixotrophic nutrition. In the presence of sunlight,it performs photosynthesis to produce its own food (autotrophic),and in the absence of sunlight,it acts as a heterotroph by preying on other smaller organisms.