$A$ : Due to bottle neck effect, among the survivors, certain alleles may be over represented, some may be underrepresented and some alleles may be totally eliminated.
$R$ : The path of extinction of a species cannot be reversed due to bottle neck effect

Which one of the following pairs of items correctly belongs to the category of organs mentioned against it?

The idea of natural selection as the fundamental process of evolutionary change was reached

Pasteur succeeded in disproving the spontaneous generation theory because

The early stage human embryo distinctly possesses