6 would be the second one
7 would be the last one
8 would be the third one
9 would say the second one
The meaning of the root prim is "first". The meaning of prim-as used in the word primitive is the early stage of an evolution or development of something, and prim just means that it was an early stage or the first.
The secondary characters in anything are essential Bc they create more possibilities for the mc and can change the plot in multiple ways and give everyone a run for their money (aka it opens up more possibilities)