. When are lipids (fat molecules) broken down into smaller molecules by your body?
when you are participating in intense exercise and need quick energy
during digestion and after you have used all of your quick energy
while you are at rest and your body has time to store energy

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.