Final answer:
True. The endosymbiosis theory proposes that mitochondria and chloroplasts arose as a result of prokaryotic cells establishing a symbiotic relationship within a eukaryotic host. This theory is supported by the resemblance of mitochondria and chloroplasts structures to prokaryotes.
Step-by-step explanation:
True. The endosymbiosis theory proposes that mitochondria and chloroplasts arose as a result of prokaryotic cells establishing a symbiotic relationship within a eukaryotic host. This theory is supported by the resemblance of mitochondria and chloroplasts structures to prokaryotes. Mitochondria and chloroplasts have their own DNA and ribosomes, similar to bacteria, and their DNA sequence and chromosome structure are highly related to their bacterial counterparts. Additionally, their binary fission process is similar to bacteria's, rather than the mitosis process performed by eukaryotic cells.