'A brief reduction in size of a population, due to natural calamities, usually leads to random genetic drift'. For this statement, identify the correct example from the following.
Human population of Pitcaim island
Polydactylic dwarfs in Amish population
Long -necked giraffe
Industrial melanism
Flippers of seal are
The presence of salts ($NaCl$ and others) in animal body fluid gives an inference that life originated in the
Man was originated in which of the following era