They lack genetic material. They lack a mechanism of motility. They lack internal membrane-bound organelles. They lack a need for proteins in their life functions.
I gave my students this multiple choice question: Which property supports the hypothesis that eukaryotic mitochondria were once prokaryotic organisms?

Only one answer is correct among these 4 choices:
- They lack genetic material.
- They lack a mechanism of motility.
- They lack internal membrane-bound organelles.
- They lack a need for proteins in their life functions.

Could you tell me which one is correct?

They lack internal membrane-bound organelles.