A model of natural selection is shown here with a small beetle population. Some green beetles in the original population are shown as dying by predation. The resulting population several generations later is shown on the right. Which of these explanations
should be selected to account for the changes in the population of beetles shown here?

The correct answer is c

By water evaporation from the leaves is created a negative pressure at the top of the tree that promotes the ascension  of the water through channels that are called xylem. there are also two molecule forces that are involved: the intra-water molecules cohesion (water molecules stick to each other) and the adhesion when the water molecules stick to the channels they are running in. this is what enables water to go from the roots to the top of a tall tree.