The best explanation for the change in plant population after selection, given the conditions of high winds and many organisms that feed on short vegetation, is:
Medium-height plants were favored by conditions that harmed tall and short plants.
This statement effectively captures how natural selection operates in this scenario. Tall plants may be more susceptible to high winds, while short plants may be consumed by ground-feeding organisms. As a result, medium-height plants have a survival advantage, leading to a shift in the population distribution toward that height.