Two scientists co-discover a population of single-celled eukaryotes that do not have mitochondria. Whoa! One scientist thinks the cells must be from a lineage that never underwent endosymbiosis, but the other scientist thinks endosymbiosis happened at some point. Which of the following provides the BEST evidence to support the second scientist?A. the cells are incapable of surviving without sunlightB. sexual reproduction is never observedC. the nuclear genome has some genes from proteobacteriaD. the cells also contain chloroplasts

D.the cells also contain chloroplasts

Explanation:

The endosymbiosis hypothesis postulates that organelles such as mitochondrion and chloroplast evolved from free living prokaryotic cells that engulfs one another for mutual benefits.  

The theory which was first postulated by Margulis Lynn (1967) explained that aerobic bacteria were ingested by anaerobic bacteria and they co-existed because the relationship is mutually beneficial to both.

The process results in double membrane organelles with their independent genome in eukaryotic cells.

Hence, the presence of either or both of mitochondrion and chloroplast in a cell is an indication that endosymbiosis  happened at some point in the history of the discovered cells.

The presence of chloroplast therefore best supports the scientist that thinks endosymbiosis happened at some point in the development of the cells.

The correct option is D.

answer; ///the correct answer to the above statement is (cytoskeleton);