Single step,large mutation is known as saltation. This statement is given by . . . . . . .

Hugo de Vries's mutation theory of organic evolution was proposed while working on:

What is a gene pool?

Darwin's theory of evolution was primarily based on which of the following concepts?

$A$: Mutations are non-directional.
$R$: Darwin's small variations are directional.

Given below are two statements regarding evolution.
Statement-$I$: Natural selection is the establishment of a phenotypic trait in changing environmental conditions.
Statement-$II$: Natural selection encourages those genes or traits that ensure highest degree of adaptive efficiency between population and its environment.
In the light of above statements, choose the most appropriate answer from the options given below.