Assertion (A) : The Darwinian theory of natural selection sometimes referred to as ‘the survival of the fittest’ explains the origin of many species as a normal process of descent from parent forms. Reason (R) : The contemporary distribution pattern of many organisms is often the result of natural migration or dispersal from original centre(s) of development. Codes

The world population is the total number of humans currently living. It was estimated by the United Nations to have exceeded eight billion in mid-November 2022. It took around 300,000 years of human prehistory and history for the human population to reach one billion and only 222 years more to reach 8 billion.