पिग्मी जैसे नीग्रिटो जातीय समूह मुख्य रूप से किस भौगोलिक क्षेत्र के मूल निवासी हैं?

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?