I have a couple of questions regarding User Requirements. The first has to do with the construction of each requirement, does each requirement need to be able to be verified? My understanding is that each requirement if not able to be verified must be able to be validated. This leads to the next question and that would be if a user requirement drives a product requirement or specification which would be verifiable and the user requirement traces to the downstream requirement then does the user requirement need to also be verified or validated? Basically, there are some questions regarding if every user requirement needs to be validated even if it has children product requirements or specifications being verified.