What is the Endosymbiotic Theory is Used to Explain

Question

What is the Endosymbiotic Theory is used to explain?
A)the rapid evolution of viruses
B)antiphagocytic abilities of parasitic protozoa
C)emergence of cell walls
D)presence of mitochondria in eukaryotes
E)development of the nucleus in eukaryotes

Accepted Answer

The endosymbiotic theory proposes that mitochondria, as well as chloroplasts in plant cells, were once free-living prokaryotic organisms that were engulfed by larger cells and developed a symbiotic relationship over time. This theory explains the presence of mitochondria and other organelles in eukaryotic cells that could not have arisen through traditional evolutionary mechanisms.