Deep ocean currents don't move as much XD
Sea wall is the structure that is built parallel to the shore that shields the coast from breaking waves. The sea walls are created to stop the brute force of the incoming waves that can destroy any structure in its path. The buildings near the shoreline would also get damaged if there were no sea walls.
Not sure if i’m answering this question correctly but african slaves started being used because native americans were dying quickly due to disease
The correct answer is - wind turbines.
The wind turbines are exclusively dependent in their energy production on the winds. The winds are not the most predictable natural occurrence, and also the energy production depends on their speed, as well as how constant they are, thus making this type of renewable energy very unpredictable.