How is a personal watercraft (pwc) propelled through the water?

By the exact definition, such a craft is jet powered and ridden astraddle but a more general definition would be a small vessel, powered by an inboard or outboard motor or sail subject to the specific regulation for such craft.

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.

Gay-lussac's law i think.