Population tend to move to the average height; not too many really short ones or really tall ones. A. Directional Selection B. Disruptive Selection C. Stabilizing Selection

Hi there the answer to this is A Directional Selection

Explanation:

Directional Selection is considered a 'positive' selection in which favored phenotypes is favored over other phenotypes causing the allele frequency to shift over time. This deals with the height from short to tall. Giraffes are a great example of directional selection.  

Hope this was correct :)  

where is the scientific experiment?