Question

The paragraph describes mitochondria and chloroplasts. WHICH sentence in the paragraph provides the strongest evidence for the endosymbiotic theory of the origin of eukaryotes?
(A) Mitochondria and chloroplasts are organelles of eukaryotic cells. (B) Mitochondria are involved in energy generation and are present in almost all eukaryotic cells. (C) Chloroplasts are involved in photosynthesis and are found primarily in plant cells. (D) In both organelles, reactions involved in the transfer of energy take place along the organelle's folded inner membrane. (E ) Both organelles can direct their own replication by splitting through a process similar to binary fission.

Answer 1

The answer is; E

This shows that these organelles were once free-living organisms  with their own mechanisms for reproduction which they have retained even after years of symbiotic relationship with the higher organisms. During their duplication, they also replicate their own DNA. Their DNA does not have histones (as opposed to the DNA in the nucleus of their host eukaryotic cell) similar to that of simple organisms such as bacteria.