### Origin of Eukaryotic Organelles
Eukaryotic cells contain membrane-bound organelles, such as mitochondria, that are absent in prokaryotes. Two hypotheses have been proposed to explain the origin of these organelles.
Hypothesis 1
Mitochondria evolved from free-living, aerobic prokaryotes that were engulfed by a larger, anaerobic host prokaryote. Instead of being digested, the engulfed cells entered a symbiotic relationship with the host cell. Over time, the engulfed prokaryotes lost their independent functions and became dependent organelles.
Hypothesis 2
Eukaryotic organelles developed through the invagination (folding inward) and subsequent pinching off of the ancestral host cell's own plasma membrane. This compartmentalization isolated specific enzymes and genetic material, allowing specialized functions to evolve within separate membrane-bound structures.
According to Hypothesis 2, eukaryotic organelles originated directly from which of the following cellular components?
- The plasma membrane of the ancestral host cellCevap
- BFree-living prokaryotes that were engulfed by a host cell
- CThe nuclear membrane of a pre-existing eukaryotic cell
- DLipid droplets suspended in the cytoplasm of a prokaryote