Which statement about limiting factors is true? a. they are the same in each ecosystem. b. they are the same for every organism. c. they vary from ecosystem to ecosystem. d. they always involve available oxygen.

The correct answer is option C, The vary from ecosystem to ecosystem

The factors which limitizes  the growth of an ecosystem are called limiting factor. The four common limiting factors are food, water, shelter and space which is same for all organisms while there are some abiotic factors that limit ecosystem growth  such as temperature, precipitation, sunlight, soil configuration, and soil nutrients which are also same. But some time there can be special factors which may limitise the ecosystem growth and thus option C is the apt answer

what's the

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.