He hormone oxytocin suppresses energy metabolism during pregnancy. reduces the ability of blood to clot during the birth process. increases a woman's appetite during pregnancy. enables the "let-down" reflex to occur when a woman breastfeeds her baby.

The hormone oxytocin enables the "let-down" reflex to occur when a woman breastfeeds her baby.

 

"Let-down reflex" occurs in breastfeeding mothers, where oxytocin acts at the mammary glands, causing milk to be “let down” into sinuses (structures from where it can be released via the nipple). Suckling by the baby is the stimulus that causes neurons that make the secretion of pulses of oxytocin from the neurosecretory nerve terminals of the pituitary gland.

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.