निम्नलिखित में से किस माप में कुल जनसंख्या को खेती के अधीन भूमि की मात्रा (कृषि योग्य भूमि) के संबंध में देखा जाता है?

In traditional anthropological classification of human races, which racial group was characterized as 'yellow-skinned'?

What is the approximate estimated proportion of ecumene (habitable) and non-ecumene (uninhabitable/sparsely inhabited) areas on the Earth's surface?