Who stated that human population grows geometrically?

In forming the theory of evolution by natural selection,Darwin was greatly influenced by

In the diagrammatic representation of the operation of natural selection,two peaks are formed. This condition shows the effect of . . . . . . .

What causes future generations to be less adapted than their parental generations?

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

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