Russian biologist konstantin mereschkowski published a work containing the endosymbiotic theory in the early 20th century. the endosymbiotic theory holds that eukaryotic cells came to exist because groups of smaller structures, such as organelles, joined together to benefit one another. the communities of structures adapted and became a single organism. many modern biologists believe that the endosymbiotic theory explains the origin of eukaryotic cells. how does this explanation of the endosymbiotic theory indicate that a eukaryotic cell is complex?
a. the explanation indicates that eukaryotic cells developed by accident.

b. the explanation indicates that eukaryotic cells developed gradually over time.

c. the explanation indicates that eukaryotic cells were developed intentionally.

d. the explanation indicates that eukaryotic cells were developed by multiple entities.