A state agency has contacted you to do a scientific assessment of kudzu in a nature preserve in southern Georgia. They are concerned about the effects of the non-native invasive vine on a small rare plant that grows on the forest floor in the preserve, but which is found nowhere else in the state. Kudzu is only growing in the east side of the preserve because it hasn't yet had time to invade further. In order to assess the effects of kudzu on the rare plant, you set up the following experiment:
Site 1. On the east side of the park with the kudzu, you set up ten 1m x 1m plots on the forest floor. In each plot, you count the number of individuals of the rare plant.
Site 2. On the west side of the park without the kudzu, you set up ten 1m x 1m plots of the forest floor. In each plot you count the number of individuals of the rare plant.
In this experiment, Site 2 is your:

a) variable.
b) control.
c) replication.
d) hypothesis.

The west side of the park as a control for the experiment because it will show the rare plants species without the kudzu. I the experiment was only done in areas with Kudzu and the scientist found that there were 3 rare species than then how would they know it this was more or less normal? Also, how would the scientist know if was the kudzu that caused the change? The west side experiment helps to answer those questions. If 3 rare species were also found on the west then we would not see any connections between kudzu and the species.