Question

1) why is it important to model an idea before making a final prototype?

Answer 1

So you Can make shore it works properly.

so you can stay on track

Answer 2

1) If you begin making a final prototype and did not create a draft, there are more room for errors and will take longer because you'll have to figure out what to do as you go rather then having the prototype laid out.

2) Brainstorming is important because having multiple ideas will allow you to rule out what you do and don't want in your design.