Answer:
The endosymbiotic theory is a scientific theory that explains how eukaryotic cells, such as those found in animals and plants, evolved from simpler prokaryotic cells. According to the theory, mitochondria and chloroplasts, two organelles found in eukaryotic cells, were once independent prokaryotic cells that were engulfed by larger cells and then evolved to become mutually beneficial partners.
Mitochondria, the organelles responsible for energy production in cells, are thought to have originated from aerobic bacteria that were taken in by an ancestral eukaryotic cell. Chloroplasts, which are found in plant cells and are responsible for photosynthesis, are believed to have evolved from cyanobacteria that were similarly taken in by a eukaryotic cell. The evidence supporting this theory includes similarities in the structure, function, and genetic material of mitochondria and chloroplasts to free-living bacteria, as well as the fact that they have their own DNA, which is similar to bacterial DNA, and reproduce through a process similar to bacterial reproduction.
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