Of the organisms (and one virus) listed below, which are composed of cells? Select all that apply. A : Euglena (a flagellate protist), Euglena gracilis B : Slime mold, Dictyostelium discoideum C : Yeast, Saccharomyces cerevisiae D : Tobacco mosaic virus E : Common sand dollar, Echinarachnius parma F : Giant tube worm, Riftia pachyptila G : Double-wattled Cassowary, Casuarius casuarius

The correct answers are option A : "Euglena (a flagellate protist), Euglena gracilis", B : "Slime mold, Dictyostelium discoideum", C : "Yeast, Saccharomyces cerevisiae", E : "Common sand dollar, Echinarachnius parma", F : "Giant tube worm, Riftia pachyptila" and G : "Double-wattled Cassowary, Casuarius casuarius"

Explanation:

All the living organisms are composed of cells, either if they are unicellular or multicellular organisms. Of the list of organisms herein shown, all of them are composed of cells except for the Tobacco mosaic virus, since virus are complex mixtures of molecules that do not fit the definition of cells. Euglena gracilis is a single-celled alga, Dictyostelium discoideum is a soil-dwelling amoeba, Saccharomyces cerevisiae is a single-celled yeast, Echinarachnius parma is a flattened sea urchin, Riftia pachyptila is a marine invertebrate and, Casuarius casuarius is a bird.