Answer: blood transfusion
Explaination:a routine medical procedure in which donated blood is provided to you through a narrow tube placed within a vein in your arm
In water molecule the electrons between the oxygen and the hydrogen are shared, but the sharing is not equal. Oxygen pulls electrons slightly towards itself. Therefore, the electrons are more near the oxygen, making that part of molecule(oxygen part) slightly negative. Since the electrons are not near the hydrogen so, that part of the molecule is slightly positive.