What is the strongest evidence for the idea that present-day eukaryotic aerobes are the descendants of the successful symbiotic association of anaerobes and aerobes?
A) Mitochondria can produce ATP.
B) A mitochondrion can survive indefinitely when removed from a eukaryotic cell.
C) A mitochondrion has its own set of DNA molecules.
D) Fossilized mitochondria are older than the oldest fossilized eukaryotes.
E) All eukaryotic cells have mitochondria.

Question

What is the strongest evidence for the idea that present-day eukaryotic aerobes are the descendants of the successful symbiotic association of anaerobes and aerobes?  
A) Mitochondria can produce ATP.
B) A mitochondrion can survive indefinitely when removed from a eukaryotic cell.
C) A mitochondrion has its own set of DNA molecules.
D) Fossilized mitochondria are older than the oldest fossilized eukaryotes.
E) All eukaryotic cells have mitochondria.

Quizplus · Accepted Answer

The fact that mitochondria have their own set of DNA molecules strongly suggests that they were once independent organisms that underwent endosymbiosis with eukaryotes. This is the strongest evidence for the idea that present-day eukaryotic aerobes are the descendants of the successful symbiotic association of anaerobes and aerobes. The other options, while relevant to the discussion of mitochondria, do not provide as strong of evidence for endosymbiosis.

What Is the Strongest Evidence for the Idea That Present-Day