The right answer is disruptive selection.
There are three main types of natural selection: directional selection, stabilizing selection, and disturbing selection. Despite the fact that all three types of natural selection have different names, they all operate in the same way: individuals who possess some form of inheritance tend to survive better and produce more offspring than individuals with inherited traits. other forms of this character.
In disruptive selection, individuals who have either extreme status of an inheritable phenotypic trait have an advantage over individuals with an intermediate phenotype. This type of selection is probably not classic, but it seems to be the cause of the beak-size differences in the black-bellied, African-beating bird population.
Not sure why the other answer was poorly rated, look up "disruptive selection graph" and the pictures are identical to the one in this question.(assuming this is the question from edge/e2020)
