Final answer:
In an experiment to test the effect of nitrogen fertilization on plant growth, the control group would be the plants that do not receive the nitrogen fertilizer. This allows comparison with the experimental group that does receive the fertilizer to evaluate the effect on plant growth.
Step-by-step explanation:
In designing an experiment to test the effect of nitrogen fertilization on plant growth, the selection of a control group is crucial for establishing a baseline to compare the effects of the fertilizer. The control group in an experiment receives an inactive treatment but is otherwise managed exactly like the other groups.
Applying this definition to your question, the potential control group of plants would be the ones that do not receive the nitrogen fertilizer. Considering the examples provided, in the scenario where a scientist plants two rows of corn with one row receiving fertilizer and the other not, the corn without fertilizer would be acting as the control group.
This is because it does not receive the experimental treatment, nitrogen fertilizer, allowing the experimenters to observe what happens to plant growth under normal conditions. This group can then be compared to the experimental group, the corn with fertilizer, to assess the impact of the nitrogen fertilizer on plant growth.