Electrical stimulation of cells is and electrical relaxation of cells is .

Electrical stimulation of the cell is depolarization, and electrical relaxation of cells is repolarization.

Explanation:

The electrical activity of the cell depends on the charges distributed on each side of its membrane, which depends on the presence of ions on each side, extracellular sodium and intracellular potassium.

A cell, like the neuron, at rest has a tendency to be negatively charged in its cytoplasm, while the extracellular space has a positive charge.

Depolarization of a cell occurs by opening the sodium channels, allowing this ion to enter the cell, resulting in a difference in transmembrane potential.  It is electrical stimulation of the cell.If the potential difference is maintained and reaches the umbral level, it produces an action potential, which in cells such as the neuron produces an electrical stimulus and in the muscle cell a contraction. Repolarization means the opening of potassium channels, the exit of this ion to the extracellular space and the return of the cell to rest.

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The answer is observations and interpreting.