REFLECTION

What element is important to life?

• The four basic elements of life are: Oxygen, hydrogen, nitrogen and phosphorus. These four elements are found in abundance in both the human body and in animals. There are other elements that compose the human body, but the four we've highlighted participate in all life processes.

Why are compounds more commonly used than

elements?

• Elements are rarely found in their pure state; compounds are much more common. ... When atoms of different kinds combine to form a compound, a new substance is created. New compounds do not have the same physical or chemical traits of the original elements. They have a new life of their own.