Mitochondria are found in most eukaryotic cells and contain their own DNA and ribosomes that are similar to those typical of many prokaryotic cells
Which of the following statements is justified by these observations?

a) the mitochondrion is the only location in which eukaryotic cells can synthesize atp
b) an ancestral cell most likely engulfed and aerobic prokaryote in a relationship that proved beneficial for both cells
c) mitochondrial membrane provide abundant surface area for reactions because of the infoldings called cristae
d) the mitochondrion plays a role in respiration but it also stores the cell's mRNA

b) an ancestral cell most likely engulfed and aerobic prokaryote in a relationship that proved beneficial for both cells

Explanation:

The evolution of mitochondria occurred when a prokaryotic ancestral cell engulfed an aerobic prokaryote. This aerobic prokaryote had the ability to perform aerobic respiration. The symbiont was sustained in the ancestral cell as the association was beneficial to both of them. The ancestral cell could drive a large number of ATP by aerobic respiration.

Gradually, symbiont lost the ability of free survival and led to the evolution of mitochondria. The presence of circular DNA and ribosomes in mitochondria similar to the prokaryotic cells prove their origin by endosymbiosis.