The replica plating experiment was performed to prove which of the following concepts?

Statement-$I$: The fitness according to Darwin,refers ultimately and only to reproductive fitness.
Statement-$II$: Those who are better fit in the environment leave less progeny than others.

The frequency of a mutant gene in a population is expected to increase, if the gene is

According to Hugo de Vries,speciation due to mutation is saltation,which means-

The idea of natural selection as the fundamental process of evolutionary change was reached by whom and when?

Given below are two statements regarding evolution.
$Statement-I$: Isolation is the separation of a population of a particular species into smaller units, which prevents interbreeding between them.
$Statement-II$: Due to isolating mechanisms, divergence and speciation do not occur.
In the light of the above statements, choose the most appropriate answer from the options given below.