4. Which of the following descriptions is incorrect for a recognized type of natural selection?
(A) Directional selection: A mode of natural selection in which individuals with phenotypes at one extreme of a trait distribution have higher fitness than those with intermediate or opposite extreme phenotypes.
(B) Stabilizing selection: A mode of natural selection that favors both phenotypic extremes over intermediates, potentially increasing variation and leading to a bimodal distribution or speciation.
(C) Balancing selection: A mode of natural selection that maintains genetic diversity in a population by favoring multiple alleles, often through mechanisms like heterozygote advantage or varying selection pressures across environments.
(D) Purifying selection: A mode of selection that removes deleterious mutations or alleles, preserving functional genetic sequences and reducing genetic variation at conserved loci.
(E) Frequency-dependent selection: A mode of selection where a phenotype's fitness depends on its frequency in the population—often, rare phenotypes have higher fitness.