The question is asking for the name of that Sea - and it's the South China Sea.
The other countries facing this sea are Taiwan, Malaysia, Brunei and Singapore.
It's a "marginal sea" because it's part of the ocean, but it's partially separated from the main part of the ocean by islands.
A tribute is wealth, often in kind<span>, that a party gives to another as a sign of respect or, as was often the case in historical contexts, of submission or allegiance. Various ancient states exacted tribute from the rulers of land which the state conquered or otherwise threatened to conquer.</span>
1:poor people got free bread and wealthy people lived on large farming estates.
2:Byzantines were regarded as leaders in the making of philosophy, metaphysics, and early physics.
