2. Water. You can die. DIE. From dehydration in a few hours.
I don't mean to be a jerk, but can you back this up in any way? I don't claim to be an expert, but I've learned a fair amount about survival (13 years on a wilderness SAR team), and about the human body (16 years in EMS...the last 10 of which I've also been a deputy coroner, paramedic school, etc), and this is the first time I've ever heard that statement.
The common phrase is the rule of 3's. 3 minutes without air, 3 hours without shelter, 3 days without water, 3 weeks without food. Obviously those are gross generalizations. But that said, I've never seen or heard of anyone in my life that died in 3 hours from dehydration. Possibly if they already had some grave underlying medical condition. Even immagining a worse case scenario, dropped out of an airplane into the middle of a desert wearing artic gear, you're still going to die from a heat related illness, not dehydration. Sure, you'll be very dehydrated, but your brain cooking after your hypothalamus shuts down is what will likely kill you, not the lack of water. So I'm just asking for a little background on where you got that info.
