The importance of random accumulation of small genetic changes is sufficient to explain evolution. Who proposed this concept?

$XX$ 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 $XX$.

What is the core essence of Darwinism?

'Population tends to increase geometrically,while food supply increases arithmetically'. This concept was put forward by

Name the type of natural selection depicted in the given diagram (Type $I$,Type $II$ and Type $III$).

Which is the most accepted theory of organic evolution?