Question: What is found in Prochlorococcus and essential for photosynthesis?
Sentence (from "Chlorophyll"): Chlorophyll (also chlorophyl) is any of several closely related green pigments found in cyanobacteria and the chloroplasts of algae and plants. Its name is derived from the Greek words χλωρός, "chloros" ("green") and φύλλον, "phyllon" ("leaf").
Relevant evidence: No