Explanation:

Euglena is a genus of single-celled flagellate Eukaryotes. It is the best known and most widely studied member of the class Euglenoidea, a diverse group containing some 54 genera and at least 800 species. SpeciesSpecies of Euglena are found in fresh and salt waters. They are often abundant in quiet inland waters where they may bloom in numbers sufficient to color the surface of ponds and ditches green (E. viridis) or red
algae "have chlorophyll as their primary photosynthetic pigment and lack a sterile covering of cells around their reproductive cells".Some authors exclude all prokaryote thus do not consider cyanobacteria (blue-green algae) as algae