Simply put, a genetic mutation comes from a change in the DNA; this change can result from an extrachromosomal element, an alteration of the inherited nucleotide... The basic building block of nucleic acids, such as DNA and RNA. It is an organic compound made up of nitrogenous, a sugar, and a phosphate group (http://www.biology-online.org/dictionary/Nucleotide)
Explanation:the farmers use raw manure on their fields because it is an excellent source of nitrogen (N), phosphorus (P) and potassium (K), which are all nutrients necessary for plants to grow and thrive.