Some scientists believe that the chloroplast and mitochondria were microorganisms that were engulfied by our cells and the cells of plants and they continue to live within these cells today. what theory is it based upon?
a. parasitism theory
b. encumbrance mutualistic theory
c. endosymbiotic theory
d. virology theory

c. Endosymbiotic theory

Explanation:

Mitochondria and chloroplasts are important cellular organelles and are related, respectively, to the process of cellular respiration and photosynthesis. These organelles have some peculiar characteristics that suggest they arose especially in eukaryotic cells. The theory that explains this idea of origin is endosymbiotic, proposed by Lynn Margulis.

According to the endosymbiotic theory, chloroplasts and mitochondria arose in eukaryotic cells because of a symbiotic association, which benefited everyone involved. According to this idea, a heterotrophic organism, which could encompass particles, phagocytized (enveloped) freely living prokaryotes capable of performing some important functions for the cell.

i believe it would be the lungs.