Assuming you still have some form of coolant (water) in your radiator then the coolant will freeze when the weather is cold enough, coolant expands when it freezes, this may cause permanent damage to your engine, such as split pipe's, burst radiator, cracked engine block
the antifreeze runs through all your water lines in your car . . . . you put it in your water tank or radiator
Nothing Nothing
if you run your engine without antifreeze your car will overheat and ruin the engine.
crack the engine block and oil mixes with water or antifreeze.
Then you fail
It will overheat because the water is needed to circulate/transfer the heat.
The engine will overheat.
The engine Burn out
If you have water instead of antifreeze in your cooling system, it will freeze! You won't be able to start the car, because the engine is connected to the water pump (which won't be able to move). If you have nothing in your cooling system (no water, no antifreeze, nothing else), then you need your head checked. Your car won't start either.
The type of car antifreeze that is safest to the environment is propylene glycol antifreeze. While it is still not totally safe, it is less toxic than other antifreeze.
it would break
My dad puts antifreeze on his car.