According to the endosymbiotic theory, some organelles found in modern eukaryotic cells may be the result of a symbiotic relationship between ancient prokaryotes. Spirulina is a specialized type of photosynthetic bacteria that is used for a variety of functions, including as a food source for animals like fish. Imagine that a Spirulina bacterium was engulfed by a prokaryotic host cell thousands of years ago, and that host cell changed over time with the bacterium inside it. Which organelle would the Spirulina bacterium have provided?
ribosomes
mitochondria
chloroplast
cytoplasm