Both euglena (eukaryote) and cyanobacteria (a prokaryote) are photosynthetic unicellular organisms found in pond water. the feature that would distinguish euglena from cyanobacteria is the

The feature that would distinguish euglena from cyanobacteria is the membrane-bound nucleus. Also, cyanobacteria do not have flagella, while euglena does. Cyanobacteria is a prokaryotic organism and thus, doesn’t have a nucleus, but unlike heterotrophic prokaryotes, cyanobacteria have internal membranes (thylakoids).

Euglena is a eukaryotic organism which contains chloroplast for the photosynthesis.

I’m going to go with b!