Have a glare from the Doctor. "If I take care of it properly, I can easily live for over 400 years in one body."

He always had run through his bodies rather quickly. But on to science. "You only have one heart, for starters. You can't see time or how it fluctuates. Most of your species has lost telepathic abilities. I could go on, but I think that gives you a good enough idea."

And he's just not even going to acknowledge that last one. Because, he proved that he doesn't have access to the TARDIS - against both of their wills. And that just hurts.