The excavates constitute a clade of eukaryotes that includes groups without mitochondria.Which of the following is the most convincing evidence that this absence of mitochondria is a derived condition resulting from a secondary loss?
A) There is a nuclear membrane in these organisms.
B) The cell membrane of these organisms is flexible and capable of phagocytosis.
C) Some of the nuclear genes of these organisms are normally associated with mitochondria.
D) In euglenids, a group in this clade with mitochondria, the mitochondria have distinctive disc-shaped cristae.
E) Other eukaryote clades have both chloroplasts and mitochondria.

Question

Quizplus · Accepted Answer

The presence of nuclear genes in excavates that are typically associated with mitochondria suggests that these organisms have lost their mitochondria secondarily, as opposed to never having had them in the first place. This is evidence that the absence of mitochondria is a derived condition.

The Excavates Constitute a Clade of Eukaryotes That Includes Groups