Question

researchers have used several pieces of evidence to support the theory of endosymbiosis. which characteristic of mitochondria and/or chloroplasts present in modern cells is one of these pieces of evidence?
both mitochondria and chloroplasts function in energy metabolism in the cell.
when taken out of cells, individual mitochondria and chloroplasts cannot survive on their own.
chloroplasts are found only in plant cells and algae, while mitochondria are found in all eukaryotes.
both mitochondria and chloroplasts have their own dna that encodes some of the proteins used by the organelles to carry out their biological functions.
many proteins used in the internal spaces of mitochondria and chloroplasts are synthesized in the cell cytosol and then transported across the organelle membranes.

Explanation:

The endosymbiosis theory suggests mitochondria and chloroplasts were once free - living prokaryotes that were engulfed by a host cell. Having their own DNA which can code for some of their proteins is evidence that they were once independent organisms. Energy - metabolism function alone doesn't prove endosymbiosis. Inability to survive outside the cell doesn't strongly support it as they have adapted to the host - cell environment over time. Their distribution in cells is not direct evidence. Protein synthesis in the cytosol and transport is a common cellular process and not strong endosymbiosis evidence.

Answer:

Both mitochondria and chloroplasts have their own DNA that encodes some of the proteins used by the organelles to carry out their biological functions.