Vitamin K antagonists (VKA) are a group of substances that reduce blood clotting by reducing the action of vitamin K. They are used as anticoagulant medications in the prevention of thrombosis, and in pest control, as rodenticides. 1  1 Mechanism of action.  2 Coumarins (4-hydroxycoumarins)
Calculate the average atomic mass of oxygen. Solution: ((15.994915*99.757) + (16.999132*0.038) + (17.999160*0.205))/100 = 15.999405 . Using our equation for determining average atomic mass, we see that the average atomic mass for oxygen is 15.999405 amu. If we check the periodic table, we will see that our average atomic mass is the same as the atomic mass indicated on the element oxygen. Ã
Mass of element. in a 70-kg person. Oxygen is the most abundant element in the earth's crust and in the body. The body's 43 kilograms of oxygen is found mostly as a component of water, which makes up 70% of total body weight. Oxygen is also an integral component of all proteins, nucleic acids (DNA and RNA), carbohydrates, and fats.