Question

A mutagen is

1: a living thing that has undergone a mutation.
2: an agent that causes a mutation in DNA.
3:a mutation that has affected one gene.
4:a chemical that can poison living cells.

Answer 1

2: an agent that causes a mutation in DNA.

Hope this helps

Answer 2

The answer would be 2. An agent that causes a mutation in DNA.

A mutagen is any agent capable of altering the genetic constitution of a cell by changing the structure of DNA.

Many forms of electromagnetic radiation such as cosmic rays, X rays, ultraviolet light and a variety of chemical compounds are mutagenic.