Text: A prokaryote is a unicellular organism that lacks a membrane-bound nucleus, mitochondria, or any other membrane-bound organelle. The word prokaryote comes from the Greek πρό (pro) ``before'' and κάρυον (karyon) ``nut or kernel''. Prokaryotes are divided into two domains, Archaea and Bacteria. In contrast, species with nuclei and organelles are placed in the third domain, Eukaryota. Prokaryotes reproduce without fusion of gametes. The first living organisms are thought to have been prokaryotes.

Question: are mitochondria part of the prokaryotic cell structure?

Available choices:
 (a). no.
 (b). yes.
(a).