Biogenic substance

A biogenic substance is a substance produced by life processes. It may be either constituents, or secretions, of  plants or animals.

Examples
 * Coal and oil are possible examples of constituents which may have undergone changes over geologic time periods.
 * Chalk and limestone are examples of secretions (marine animal shells) which are of geologic age.
 * Cotton and wood are biogenic constituents of contemporary origin.
 * Pearls, silk and ambergris are examples of secretions of contemporary origin.

Biogeen Biogen