जनांकिकीय संक्रमण सिद्धांत (Demographic Transition Theory) को वारेन थॉम्पसन द्वारा प्रारंभ किया गया था और बाद में किसके द्वारा विस्तारित किया गया?

A large portion of the non-ecumene region of the Earth has remained sparsely populated primarily because of:

A significantly low sex ratio (fewer females per male) is most typically associated with which type of urban centers due to male-selective migration?