During repolarization of nerve

Which of the Following takes place during impulse conduction during depolarisation of nerve impulse -

During conduction of nerve impulse, what causes repolarisation of nerves ?

What happens during repolarization?

Which of the following option is correct for the statement 'X' and 'Y'? Statement 'X' : Immediately after repolarization, ionic imbalance is created on both the sides of nerve fibre. Statement 'Y' : During repolarization K^(+) ion channel open up and K^(+) ion moves on innerside of plasma membrane. Options :

At the end of repolarization, the nerve membrane gets hyperpplarized. Why ?

In ECG the repolarization of ventricles is indicated by

In ECG the repolarization of ventricles is indicated by