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 independent prokaryotes that were engulfed by a host cell. The presence of DNA in mitochondria supports this as it suggests they were once autonomous organisms. DNA in the cell nucleus, ribosomes, and cytoplasm is not evidence for this theory.

Answer:

A. DNA in mitochondria