Which is the basis of evolution?

The presence of deleterious alleles in a heterozygous genotype in a population is called......

Select the correct option for gene flow.

$XX$ 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 $XX$.

Darwinian fitness can be estimated by

Which of the following conditions represents hybrid breakdown?