Define mutagen and describe how mutagens are used in genetic research.

A mutagenic agent is any chemical, physical or biological compost that can induce a mutation in the cell's DNA, making this mutation pass to the next generation.

Mutagenic agents are widely used in the fields of biotechnology, genetic engineering, medicine and agroindustry. This is because these agents have helped in the advancement and development of new technological tools.  

In genetic research some bacteria and viruses are used by agribusiness companies to obtain transgenic beings. These mutagenic (biological) agents act as vectors of laboratory-created genes that will insert these genes into an organism to be modified. It could be, for example, a gene that will improve maize resistance against a pest. Thanks to mutagenic agents, this genetic information can be passed on to the organism, in this case, the plant.

b.have there own function.

affects the water bodies: excessive use of fertilizers causes eutrophication. the fertilizers which are used on plants affect the quality of land on which it is used, further causing erosion of soil. the fertilizers used on plants contain harmful chemical fumes which affect the environment.