Genetic drift operates in

$A$: $A$ single large mutation called saltation can produce new species.
$R$: Mutations are directional.

$XX$ is a type of selection process in evolution. $XX$ promotes population changes in one particular direction. $XX$ favours small or large-sized individuals,and the mean size of the population changes in $XX$. Identify $XX$.

$A$ major criticism of Darwinism is that it....

Hugo de Vries's experimental organism was

Which of the following are correct examples of evolution by anthropogenic action?