As you can observe, we only have one data given which is the mass of the body. In order to solve this, we must know of the percentage of phosphorus in the body. Since it is not given, we look for it in literature. Based on the diagram attached showing the relative abundance of elements in our body, phosphorus only takes up 1%. Therefore, the mass of phosphorus in the 43-kg body is:
Mass of phosphorus = (43 kg)(0.01) = 0.43 kg