You boil water that has been extracted from a swamp and find there are archaea that are still alive. these archaea are most likely

The archaea seen from the water even when boiled is most likely thermophiles. If an organism is thermophile, then it means that the organism can withstand relatively high temperatures—meaning that the archaea have survived the boiling water because of its characteristic of being a thermophile.

the answer would be   10%