Which organism's theory emphasizes the relationship between certain eukaryotic cells and prokaryotes?

The Endosymbiotic Theory is a significant concept in biology that describes how certain organelles in eukaryotic cells, such as mitochondria and chloroplasts, originated from prokaryotic organisms through a process of symbiosis. This theory suggests that early eukaryotic cells engulfed prokaryotic cells, which then formed a mutually beneficial relationship. Over time, these prokaryotic cells became integral parts of the eukaryotic cells, providing them with new capabilities, such as aerobic respiration or photosynthesis.

This theory is supported by various lines of evidence, including the fact that mitochondria and chloroplasts contain their own DNA, which is similar to bacterial DNA, and possess double membranes, consistent with the engulfing process. Additionally, these organelles replicate independently of the eukaryotic cell cycle, further supporting the idea that they were once independent prokaryotic organisms.

The other options do not focus on the relationship between eukaryotic and prokaryotic cells. For example, the Cell Division Theory pertains to the process by which cells replicate, while Cell Theory outlines the fundamental principles regarding the structure and function of all living cells. The Photosynthesis Theory relates specifically to how organisms convert light energy