The excavates are a clade of eukaryotes that includes groups without mitochondria.What 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 fact that some of the nuclear genes of these organisms are normally associated with mitochondria supports the idea that the absence of mitochondria in excavates is a derived condition resulting from a secondary loss. It suggests that these organisms had mitochondria at some point in their evolutionary history, but lost them through adaptation or other environmental factors. The other options listed are not as specific to the loss of mitochondria in this clade.

The Excavates Are a Clade of Eukaryotes That Includes Groups