A keystone species is an organism that helps define an entire ecosystem. By keeping populations of mussels and barnacles in check, this sea star helps ensure healthy populations of seaweeds and the communities that feed on them—sea urchins, sea snails, limpets, and bivalves.
Eukaryotes are larger cells with membrane-bounded organelles. Prokarotes are not that large and do not have a nucleus or any memberane-bound organelles.
Alcoholic fermentation; carbon dioxide. Alcoholic fermentation produces alcohol and carbon dioxide in bread. The alcohol evaporates during the baking process.
