Question

Researchers have found that mitochondria and chloroplasts in eukaryotic cells have their own DNA. This DNA is different from the DNA in a eukaryotic cell's nucleus. Chloroplasts and mitochondria use their own DNA and ribosomes to make some organelle-specific proteins.
What statement is best supported by this information?

A.
Modern cells could exist without mitochondria and chloroplasts.

B.
Early eukaryotic cells engulfed prokaryotic cells, which later became mitochondria and chloroplasts.

C.
Early prokaryotic cells engulfed eukaryotic cells, which later became mitochondria and chloroplasts.

D.
Mitochondria and chloroplasts could exist outside of modern cells.

Answer 1

Option A and D are totally incorrect because the cell and mitochondria and chloroplast are co dependent on each other.
We can say that the eukaryotic cell provides protection to mitochondria and chloroplast and in turn they provide energy.

Option C is incorrect too because prokaryotes being inferior to Eukaryotes ,cannot engulf them.
So in my opinion option B should be correct because of endosymbiosis theory which says that Superior cells engulf the prokaryotes without digesting them. So that the prokaryotes living inside the eukaryote can provide it energy and the superior cell provides the protection to the inferior one.

hope u get it, thank you