Nitrogen occurs in air as N2 which is not readily available to organisms.
Many elements occur in nature in various forms. Not all forms in which elements occur in nature are usable. Some forms in which elements occurs can not be used unless they undergo some kind of extraction and purification process.
Two elements are abundant in nature but not in a readily available/usable form are nitrogen and silicon. Nitrogen occurs in air as N2 which is not readily available to organisms. Silicon abundant in soil and is used in making glass but must be processed before it can be used.
Learn more about silicon: https://brainly.com/question/18902047
