Final answer:
The true statement about mitochondrial and chloroplast genomes is that they can replicate independently of nuclear DNA, supporting the endosymbiotic theory that posits these organelles are of prokaryotic origin.
Step-by-step explanation:
The correct statement regarding mitochondrial and chloroplast genomes is B) They are able to replicate independently of the nuclear DNA. Both mitochondria and chloroplasts contain their own DNA, which is different from the DNA found in the cell nucleus. Their DNA is circular, similar to that of bacteria, which supports the endosymbiotic theory — the idea that these organelles were once free-living prokaryotes that entered into a symbiotic relationship with early eukaryotic cells. Mitochondrial and chloroplast genomes can replicate through processes similar to bacterial binary fission, independent of the cell's nuclear DNA replication cycle. Moreover, while they do have genes necessary for certain functions such as the electron transport chain in mitochondria, they do not contain all the genes necessary for their function; some are found in the cell's nucleus. Also, contrary to some of the incorrect options, mitochondrial and chloroplast genomes do encode important protein-coding genes and are not just limited to ribosomal and transfer RNAs.