Which two components are required to ensure power redundancy for a blackout period extending over 24 hours

Look at the map of cities in the united states at the turn of the twentish century what impact did railroads have on cities across the united states at the turn of the twentish century

What would you call a political system that is only meant to last for a short time

What are the most populous and least populous areas of russia? and why are some areas more heavily populated than others?