Answer:
The cells would not be able to produce energy.
Step-by-step explanation:
There are aerobic cells in the human body such as nerve cells, which is a process where oxygen is used to produce ATP in much greater amounts.
They go through a process named "oxidative phosphorylation" which is where the electron transfer happens taken from the NADH and down to FADH2 and lastly to the oxygen molecules to produce ATP.
If these cells have their oxygen cut out, then oxidative phosphorylation can not proceed which blocks the formation of ATP, leaving the cells without energy to operate.
I hope this answer helps.