alga

noun1

1. •
   Any of many aquatic photosynthetic organisms, including the seaweeds, whose size ranges from a single cell to giant kelps and whose biochemistry and forms are very diverse, some being eukaryotic.

   • For example, the antitumour depsipeptide kahalalide F was isolated from the opisthobranch mollusc Elysia rufescens, and is used by both the mollusc and its dietary alga Bryopsis spp. — 2016