Question

the endosymbiotic theory helps to explain the origin of which structures?
○ mitochondria
○ ribosomes
○ nuclei
○ cell membranes

Explanation:

The endosymbiotic theory proposes that eukaryotic cells evolved from prokaryotic cells that engulfed other prokaryotes. Mitochondria (and chloroplasts) are thought to have originated from free - living prokaryotes that were engulfed by a host cell and developed a symbiotic relationship. Ribosomes are present in both prokaryotes and eukaryotes and their origin is not explained by the endosymbiotic theory. The nucleus and cell membranes have different evolutionary origins not related to endosymbiosis.

Answer:

A. mitochondria