Directional selection can be distinguished from disruptive selection by
a.
the elimination of extreme variations of traits
b.
selection for two extreme variations of a trait
c.
the preservation of gene frequencies
d.
selection for one extreme variation of a trait

a "theory" a suggestion that is not 100 % accurate, or a figure. some people say its a theory because they of all the passed theory's about one subject. it depends sometimes theory might be accurate and sometimes they are.

her next move would be to use agarose gel electrophoresis to separate the dna molecules of varying length and create a dna fingerprint.