Which of the following statements describe natural extinction ?
(i) Extinctions abetted by human activities
(ii) Slow replacement of existing species
(iii) Also known as background extinction
(iv) A small population is most likely to be extinct

Options

A. (i) and (ii)
B. (i), (ii) and (iii)
C. (ii), (iii) and (iv)
D. (i), (ii), (iii) and (iv)

Answer

C

Explanation

Natural or background extinction is a slow process of replacement of existing species with the better adapted species due to alternate evolution, changes in environmental conditions, predators and diseases. A small population due to inbreeding depression (reduces genetic variability) and normal population fluctuations during unfavourable periods like drought, harsh winter or severe summer.