You go on a trip to the South Pole, Antarctica. Unfortunately, you catch a bacterial infection from a tea mate while you’re there, and you experience sore throat, fever, productive cough, and headache. The organism causing your illness is a psychrophile. mesophile.
thermophile.
psychrotroph.
anaerobe.

that scientist would be robert hooke

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.