What do you mean by boundary? You mean the difference between being friends with someone and being friendly with someone?
I don't think there is a hard boundary, it's a pretty fluid transition.
I think that can’t be answered categorically like that. Some species can survive being completely frozen, like the wood frog, others can’t. Interestingly, there are also some mammals that can survive extreme cold, the arctic ground squirrel can survive a core temperature of below 0°C
I guess it’s as doctors say: “You aren’t dead until you’re warm and dead”
Those of you who are friendly with your coworkers but no friends, where exactly do you lay the boundary?
Can cold-blooded animals die of hypothermia?