Which is a point mutation and not a frameshift mutation? mutagen insertion deletion silent

Below is the step-by-step explanation: 1. **Definition of Point Mutation:** A point mutation is a change of a single nucleotide in the DNA sequence. One example is a silent mutation, where the change in the nucleotide does not change the amino acid that is produced due to the redundancy in the genetic code. 2. **Definition of Frameshift Mutation:** A frameshift mutation occurs when nucleotides are inserted or deleted in numbers not divisible by three. This causes a shift in the reading frame of the codons, which is a more drastic change than a single nucleotide substitution. 3. **Analyzing the Options:** - **Insertion:** An insertion mutation can be a point mutation if it involves a single nucleotide, but if it is not a multiple of three, it causes a frameshift. - **Deletion:** Similar to insertion; if it's a single nucleotide it might be a point mutation, but if it's not in multiples of three, it results in a frameshift. - **Silent:** A silent mutation changes a single nucleotide but does not change the amino acid coded, and importantly, does not result in a frameshift. - **Mutagen:** A mutagen is an agent that causes mutations, not a mutation itself. 4. **Conclusion:** The option that is a point mutation and not a frameshift mutation is the **silent mutation**. Thus, the answer is: **silent**.