I'd like to add that, while much of the crew is quite young, it's by no means a middle-school field trip. Mordin is nearing the end of his natural lifespan, Miranda is implied (or stated - I don't remember and I'm too lazy to look it up) to be significantly older than she looks (blah blah genetic perfection blah blah), and Samara is at least several centuries old. While we're on the subject, is it just me or does anyone else wonder why quarian, volus, hanar, and elcor lifespans aren't discussed? Every other species gets a line in the Codex about how long they live compared to other species, but not those three. I can understand ignoring the "background" races, because they don't affect much, but the quarians are a much bigger deal. I'd guess they have slightly shorter lifespans than humans and turians, but a canon number would be nice.