This is known as the Anaconda Plan.
This military strategy, developed by Union General Winfield Scott, was meant to starve the Confederacy out of their resources. Essentially, Scott felt that if the Confederacy could not trade for goods with other countries they would not be able to survive. This is due to the Confederacy's reliance on cotton as their main cash crop.
This strategy helps to explain why the US wanted to blockade trade with other countries as well as why the Union wanted to control the Mississippi River, as they knew control of this waterway could negatively impact the Confederacy's ability to transport/obtain resources.
Christopher Columbus was instructed by the King, and Queen of Spain to travel to the new world in search of valuable natural resources. Columbus had his own inclinations to travel being that the idea that the world was spherical had not yet been a well accepted fact.
Advantages: animal produce high yield due to the less wast of energy
Disadvantage: much capital construction of a zero grazing unit
I don't think it should be taken at face value because those ways could be the main ways to earn money, but it could probably be the least reliable or successful ways. This sentence could just be a lie taken literaly in which has a hidden meaning. This could be a meaning that you might not get, in which will leave you ripped off.