वह चरण जहाँ जनसंख्या वृद्धि नगण्य या स्थिर हो जाती है, निम्नलिखित में से किस विशेषता द्वारा दर्शाया 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?