Question

Choose the answer that best describes the Theory of Endosymbiosis.

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The ancestors of chloroplasts and mitochondria were once free-living
simple prokaryotes that formed a symbiotic relationship with other cells
The ancestors of chloroplasts and nuclei were once free-living simple
prokaryotes that formed a symbiotic relationship with other cells
The ancestors of chloroplasts and mitochondria were once free-living
simple eukaryotes that formed a symbiotic relationship with other cells
The ancestors of nuclei and mitochondria were once free-living simple
eukaryotes that formed a symbiotic relationship with other cells

Answer 1

The Theory of Endosymbiosis explains that chloroplasts and mitochondria were once free-living simple prokaryotes that formed a symbiotic relationship with other cells.

Step-by-step explanation:

The correct answer is:

The ancestors of chloroplasts and mitochondria were once free-living simple prokaryotes that formed a symbiotic relationship with other cells.

The Theory of Endosymbiosis proposes that eukaryotic cells evolved from a mutualistic relationship between multiple independent prokaryotic cells. According to this theory, ancestral cells engulfed free-living prokaryotes, such as bacteria, which eventually evolved into organelles like mitochondria and chloroplasts.

An important piece of evidence supporting this theory is that mitochondria and chloroplasts have their own DNA, similar to bacteria, suggesting that they were once separate organisms.

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