posted by candianon .
You are conducting an experiment to determine whether lichen populations are affected by local airborne pollutants. Which of the following observations would best support your hypothesis that high levels of airborne pollutants cause a reduction in lichen abundance:
a) lichens growing in areas with high levels of SO2 tend to grow in smaller, but more numerous colonies
b) areas with high NO2 levels tend to have fewer of the species of tree that lichens prefer to grow on
c) lichens are abundant where rainfall has been determined to be low in dissolved pollutants
d) lichens in suspected polluted areas have a significant increase in the proportion of sulphur and nitrogen absorbed
e) none of the above observations would support my hypothesis
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