Answer:
True.
Step-by-step explanation:
Mitochondria and chloroplast are the important cell organelle present in the organism. Mitochondria is used for the generation of ATP whereas chloroplast is used for the photosynthesis in plants.
Endosymbiont theory explains the evolution of mitochondria and chloroplast. According to this theory, the free-living prokaryotes taken from the inside of other prokaryotes and later evolve into mitochondria and chloroplast.
Thus, the correct answer is option (a).