UGC NET Questions (Paper – 1)

Public health measures, better nutrition and control of epidemics often reduce death rates quickly. However, cultural and socio-economic factors cause birth rates to remain high for some years. This combination of low mortality and high fertility leads to very high natural increase, called population explosion. Over time, fertility also declines, but the lag creates a phase of fast growth.

Option A:
Option A is incorrect because fertility alone usually does not rise sharply in the transition; mortality change is the main driver of the explosion phase.

Option B:
Option B is correct as it explains how early mortality decline with delayed fertility decline produces rapid growth, especially in developing countries in mid-transition.

Option C:
Option C is incorrect since simultaneous decline in both fertility and mortality would limit growth; there would be no “explosion”.

Option D:
Option D is incorrect because migration plays a relatively smaller role in national-level population explosions compared with vital rates.