If it's for a grad position I am tempted to assume it's somewhat of a trick question. They might not care about those three things themselves but actually the concept of importance and its subjectivity. By this I mean, perhaps you would do better to discuss the concept of importance, and that in order to apply a value of importance to anything, we need information such as: Important to whom? Important to what end? Important in what context? etc. What criteria does a given thing need to meet in order to be accepted as important?
Is importance dictated by desire? Is it dictated by life? For example, electricity is most certainly not important as far as staying alive is concerned, since we most certainly survive without it. Is food important? Absolutely, since we die without it. In a context of life/death, none of those three things hold any importance whatsoever. This is of course only true if we mean electricity as utility rather than electricity as a part of nature (which powers our brain etc).