A scientist has found a correlation between the amount of
soil erosion in an area and the number of trees cut down in
that area. In areas where more trees were cut down, the
rate of soil erosion increased. The scientist wants to find
out whether cutting down trees caused the soil erosion.
What could the scientist do to help distinguish between correlation and
cause?
O A. Compare soil erosion rates in the area with those in areas without
trees, such as grasslands, to find out whether factors other than
trees affect erosion.
OB. Compare the rates of soil erosion before and after the trees were
cut down in that area to find out whether both factors changed.
O C. Compare soil erosion in areas with heavier rainfall than the
studied area to find out whether other factors are involved.
O D. Measure soil erosion rates after new trees are planted in an area
to find out whether adding trees has the opposite effect.