Not completely sure, but maybe C.?
I think the correct answer from the choices listed above is option A. Directional selection can be distinguished from disruptive selection by the elimination of extreme variations of traits. Directional selection is a natural selection where an extreme phenotype is favored than others.
Answer:
A. It is a source of genetic variation
System that removes solid and liquid wastes is called excretory system.
Hope this helps~
