Wanda is in labor. which hormone is causing her uterus to contract for childbirth?

Oxytocin Hormone

Explanation:

It is the oxytocin which is mainly responsible for contraction of womb along with lactation during child birth.

The muscles of uterine are stimulated by the oxytocin to release prostaglandins and cause further contraction.

Oxytocin also stimulates cervix  ripening  thereby leading to successive dilation during labour however Oxytocin, suring this time help in maintaining the  high levels of oestrogen.

an active site is a region that is present on an enzyme where the reactants or the substrate molecules we can say bind and experience a chemical reaction. the substrate is basically a reactant whose concentration is changing and that is converting into a product after binding at the active site of an enzyme