Answer: Oxidized when electrons are passed to the electron transport chain NADH molecules formed during glycolysis and in the Krebs cycle are oxidized when electrons are passed to the electron transport chain.
Explanation: Hope this helped! :)
This basically electrophoresis so it requires understanding where certain parts of the gel match I suggest a reference
you didn't list choice but i'm guessing chloroplasts
Wouldn't the tree be twenty years old. Since each ring is 1 year.