Primer that Is Well Designed Forms Most Significant Element of PCR Queries

I’m stuck on a Biology question and need an explanation.

1. What is the purpose of the final 60 minute extension for Taq polymerase’s non-template adenylation? [2]
2. How are PCR primer’s designed? What would happen if you had a primer binding site mutation in a person’s DNA? [5]
3. Describe three mechanisms in which inhibition can occur in a forensic sample. [3]
4. What does multiplexing mean? [2]
5. Why does stutter occur during amplification? [2]
6. What type of repeat is the most common in forensic STR kits? [2]
7. Would you expect a pentanucleotide repeat to have more or less stutter than a tetranucleotide repeat? Why? [2]