Which is represented by the X?

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.

Well i had the same answer, so the correct answer would be a. but in this case it would be the one with plasma membrane and cell wall circled that is next to the hairy pill type of thing.