The diagram below shows the process of natural selection. Choose the correct option for $P, Q$ and $R$.

Genetic drift does not apply to:

Industrial melanism is an example of

Given below are two statements.
Statement $I$ - According to Darwin,the gradual,inheritable variations over a long period of time lead to speciation.
Statement $II$ - According to Hugo de Vries,mutations are the cause of variations.
In the light of above statements,select the correct option given below:

The evolution of species is based upon the sum total of the species' adaptive changes preserved by:

As a result of the excessive use of herbicides and pesticides,which types of varieties were selected in a short period?