A scientist is testing a new fertilizer on a crop of corn. She divides a field into two sections. One section receives the new fertilizer, while the other receives no fertilizer. Both sections receive the same amount of water and sunlight. What is the independent variable in this experiment?

The correct answer to the question "A scientist is testing a new fertilizer on a crop of corn. She divides a field into two sections. One section receives the new fertilizer, while the other receives no fertilizer. Both sections receive the same amount of water and sunlight. What is the independent variable in this experiment?" is Option C: The presence or absence of the new fertilizer.

The other options — A) The height of the corn plants, B) The amount of water given to the plants, D) The amount of sunlight received by the plants — are incorrect for this GED Exam Prep question. As explained above: The independent variable is the factor that is intentionally changed or manipulated by the experimenter. In this case, the scientist is changing whether the corn receives the new fertilizer or not.