We at last have a reasonable answer to the original problem. Be sure that you understand the ways in which we improved the model, the method, and the implementation in arriving at an answer.
There's one last step in the assessment process: we need to ask whether the problem that we've just solved has anything to say about the question that we originally asked. In the beginning, we were wondering whether or not the world is overpopulated. Does the fact that there were around 310,000 square feet per person in 1990 help you decide whether or not the world is overpopulated? Try to answer that question yourself. While you're at it, think about what role scientists and engineerings should play in shaping public policy.