Afamily has seven sons. the chance that their eighth child will be a daughter is

one chance in seven
one chance in eight
one chance in two
practically none

Biochemistry, it deals with the chemical constitution, the breakdown and the synthesis of plant and animal products.

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.