A group of 500 people are selected at age 2 no0 and followed for 15 years. The people who go on to develop a certain type of cancer are compared those who do not. The researchers attempted to determine different factors that could increase cancer risk

Phosphorous can form an ion called phosphide, which has the formula p3−. this ion can form an ion called phosphide, which has the formula p3−. this ion properties very similar to those of pforms when a phosphorus atom loses three protonsis called a cationcontains 18 electrons