In a Mendelian population,genetic drift occurs in which of the following?

The concept that "Population tends to increase geometrically while food supply increases arithmetically" was put forward by:

$XX$ 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 $XX$.

In the case of the peppered moth $(Biston \text{ } betularia)$, the dark-colored form became more prevalent than the light-colored form in England during the Industrial Revolution. This is an example of:

Observations from England support evolution by natural selection. Before industrialization, $P$ moths were more abundant on trees, whereas after industrialization, $Q$ moths were more abundant. Identify $Q$.

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.