Question

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endosymbiotic theory
which statement is evidence used to support the endosymbiotic theory?
mitochondria and chloroplasts reproduce similar to eukaryotic cells: through mitosis.
mitochondria and chloroplasts are surrounded by one membrane.
mitochondria and chloroplasts contain their own dna.

Explanation:

The endosymbiotic theory states that mitochondria and chloroplasts were once free - living prokaryotes that were engulfed by a larger cell. One of the key pieces of evidence is that mitochondria and chloroplasts have their own DNA, similar to prokaryotes (prokaryotes have circular DNA, and mitochondrial and chloroplast DNA is also circular in nature).

• The first statement is incorrect because mitochondria and chloroplasts reproduce through binary fission (similar to prokaryotes), not mitosis (which is the division of eukaryotic cells).
• The second statement is incorrect as mitochondria and chloroplasts are surrounded by two membranes (an inner and an outer membrane), which is consistent with the idea that they were engulfed (the outer membrane would be from the host cell and the inner from the prokaryote itself).
• The third statement “Mitochondria and chloroplasts contain their own DNA” is correct evidence for the endosymbiotic theory.

Answer:

Mitochondria and chloroplasts contain their own DNA.