Undergraduate / Starting an admission essay on important discoveries being the result.. [4]

I have to write an admission essay to get into a Magnet high school. I have to use this prompt: "Are all important discoveries the result of focusing on one subject?"

Instructions: Plan and write an essay in which you develop your point of view view on this issue. Support your position with reasoning and examples taken from your reading, studies, experience, or observations.

My view is that it is not the result of focusing on one subject because there have been many cases in which new things were creating without meaning.

I'm having trouble thinking of how to start and write the whole paper.
I also have some questions about this..

How long does this kind of essay need to be? (paragraphs)
How should I use DRAPES in this essay?

Also, any other pointers? This is my first time writing an essay for admission.

Thanks much!