In some oceans, large underwater mountains exist. Corals inhabit some areas of these underwater mountains but not others. Scientists studied the effect of the presence of corals on the types of other organisms in these habitats. To do this, they collected water samples from areas with corals and areas without corals and compared the organisms found in each sample. How does this method of sampling help determine the effect of the presence of corals on the types of other organisms?A. by comparing the populations of organisms found in the samples from the two areasB. by comparing the lifespans of the organisms found in the samples from the two areasC. by comparing the average size of the organisms found in the samples from the two areasD. by comparing the average mass of the organisms found in the samples from the two areas