What is the name given to half of the earth that contains africa, australia, europe and their waters?

Which caused demand for farm products to decline after world war i

Ineed to try to get this right so i can get a good grade so can someone me

All of the following effects occurred as a result of roman expansion following the punic wars except it brought in great wealth from conquered territories it allowed many romans to buy large farming estates it provided slave labor for the large farming estates it caused the roman economy to decline due to the high cost of war