If a mutation results in an organism with new characteristics then eventually a new species will be formed if more such mutations will continue to accumulate in the individual. Mutations result into the accumulation of variations in an individual and when such variations keep on accumulating in a particular organism consistently it leads to formation of a new species or we can say that evolution has occured.
Depolarization is initiated when there is an influx of sodium inside the cell as opposed to repolarization, where potassium exits the cell (occurring after Na+ gates close). Remember that for every 3 Na+ in, there is 2 K+ out. This imbalance helps to stabilize the membrane.
Answer:
Nuclear energy because it can never be reused again
