Im guessing here but i think it's true
Answer:4
Explanation:To balance the equation you need to make the number of each element equivalent in both sides.
To start add a 2 in front of the MnO2 which balances the Mn.
Then balance the oxygen by adding a 4 in front of H20.
The H then needs a 8 as it’s coefficient.
In the cellular respiration,02 and C 02 exchange is there
so the answer is C 02 diffuses passively out of the cell