What is the functional significance for the convoluted folded shape of the inner membrane of the mitochondria referred to as the cristae?

The function of folded shape of inner membrane of the mitochondria referred to asthecristaeis to increase the surface area of mitochondria and the enzymes for respiratory site (electron transfer system).

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.