On an unrelated note, was no one else bothered by the appearance of food and CHEESE in an environment devoid of all animal life? It really bothered me more than I care to admit. If they could replicate yeast (bread for sandwiches) surely human bodies arent that big an upgrade?
I get your point and also agree with it to an extent, but I'm not quite on board that the jump from single-celled, eukaryotes in yeast to complex human bodies is not "that big an upgrade."
Consider that it took evolution billions of years to make that change, for starters. For an alien species - even an advanced one - to get to that point in the space of a few months would be particularly astounding.
Secondly, consider that on a world that can support life, single-celled organisms of some kind are probably going to be the "first stop" on the way to more complex forms of life. So they've probably seen some sort of organism that, if not identical to yeast or bacteria, is probably remarkably similar.
After that point, though, I think it's quite likely that evolution could diverge widely from the path it took on earth, making it that much harder for them to understand the workings of the human body.