When populations of two species work together to obtain resources, they are OA
competing
ОВ.
cooperating
OC
pioneering
OD
arguing

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.

answer///triple meter;