The primary enemy naval combatant was the Imperial Japanese Navy (IJN) against Britain, US, Australia, etc.
baltic sea
Besides air strikes on land and sea targets, they were used "for the first time" to contest control of the sea (more commonly called "Sea Battles"). Instead of battleships fighting it out; carriers fought it out...first at Coral Sea, later at Midway.
Land locked. They didn't have access to the sea.
pirates yep cannon balls
The Lusitania was sunk
Land, sea and air were the arenas used.
There were many African countries that became independent immediately after World War 2. This was because the European countries that had ownership over the African countries were broke after the war and had no more money to deal with rebuilding the African countries.
Global war against terrorism.
baltic sea
It's called WW2 because it was the second world war to have happened. It, at the end, had involved over 70 countries, which included us. And those 6 countries above, yeah, they were not the only ones involved, nor are they, combined, close to half the world. However, they were indeed in WW2 along with the other nearly 70 countries.
a war
Most of the fighting was in Europe. There was only 1 major Naval battle, in the North Sea, called Jutland or the Skaggerak, in 1916. There was also fighting in the Middle East & in Africa.
World War 2 was the most widespread war in history, but the fighting was most heavy in Europe, the Atlantic and Pacific Oceans, the Mediterranean Sea, North Africa, and East Asia.
The Kingdom of Serbia had 707,343 men fighting in World War I.
3
Transporting war material across the sea; convoys.
Marines are usually fighting in the sea, so if there were no marines, then there would be more attack's from other countries who came by using the sea.