Answer: (1)
Alga is a term that describes a large and incredibly diverse group of eukaryotic, photosynthetic lifeforms. These organisms do not share a common ancestor and hence, are not related to each other (polyphyletic).”
Algae possess cell walls made of glycoproteins and polysaccharides such as carrageenan, cellulose, hemicellulose and pectins and agar that are absent from land plants. In bacteria, the cell wall is composed of peptidoglycan.