Supply side economics is an economic theory that suggested that lowering the tax to corporate, government will help in create interest in investing more to industry that will help in enhancing productivity and create jobs and eliminate inflation by slashing down prices.
This idea is an enormous piece of Ronald Reagan's financial arrangements during his administration. This turns into a focal point of "Reaganomics." He utilizes this strategy to drive the American economy during his 8 years of presidency.
The alliance system meant that countries were obliged to help other allies so if one declared war, the others had to do the same. Without the alliance system, WW1 would have been a lot smaller and probably not a world war since fewer countries would become involved.