Answer:
The endomembrane systemis a group of membranes and organelles in eukaryotic cells that works together to modify, package, and transport lipids and proteins.
C6H12O6+6O2--->6CO2+6H2O+energy
Oxygen(O2) is used to break down glucose(C6H12O6) into energy so the answer is b
The answer is D) twice.