Question

which discovery supported the endosymbiotic theory?
○ dna in mitochondria
○ dna in the cell nucleus
○ dna in ribosomes
○ dna in the cytoplasm

Explanation:

The endosymbiotic theory proposes that mitochondria (and chloroplasts) were once free - living prokaryotes. Prokaryotes have their own circular DNA. The discovery of DNA in mitochondria supports this theory as it suggests mitochondria have their own genetic material, similar to prokaryotes. DNA in the cell nucleus is typical of eukaryotic cells, ribosomes do not have DNA, and DNA in the cytoplasm is not a specific support for endosymbiosis as described.

Answer:

A. DNA in mitochondria