Question

dna mutations
quiz complete
a mutagen is
o a living thing that has undergone a mutation.
o an agent that causes a mutation in dna.
o a mutation that has affected one gene.
o any chemical that can poison living cells.
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Explanation:

A mutagen is defined as an agent (which can be chemical, physical like radiation, etc.) that causes a change (mutation) in the DNA sequence. Let's analyze each option:

• Option 1: A living thing that has undergone a mutation is called a mutant, not a mutagen.
• Option 2: This aligns with the definition of a mutagen.
• Option 3: A mutation affecting one gene is just a type of mutation (point mutation if it's a single - nucleotide change), not a mutagen.
• Option 4: While some mutagens are toxic chemicals, not all chemicals that poison cells are mutagens. Mutagens specifically target DNA to cause mutations.

Answer:

an agent that causes a mutation in DNA.