The theory of natural selection is based on which of the following?

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 $Q$.

Who proposed the theory of continuity of germplasm?

Given below are two statements regarding evolution.
$Statement-I$: Selection against harmful mutation leads to a mutation balance.
$Statement-II$: In mutation balance, the allele frequency of harmful recessives keep on changing generation after generation.
In the light of above statements, choose the most appropriate answer from the options given below:

Darwin,in his 'Natural Selection Theory',did not believe in any role of which one of the following in organic evolution?

The frequency of traits increases when they are ........