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 is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.