Final answer:
The subject is Biology, and the question pertains to the high school grade level, specifically focusing on the impact of Flower Power fertilizer versus regular watering on plant flower production.
Step-by-step explanation:
The question SpongeBob wants to answer is whether using Flower Power fertilizer will help plants produce more flowers compared to regular watering. This is a biological inquiry since it deals with plant growth and the effectiveness of a fertilizer product. It is at the high school level, covering principles that might be found in a high school biology course focused on botany or plant science.
In a related experiment mentioned, a student tests the relationship between plant growth and the presence of detergent in the soil. The issue with this experiment is that the control and variable groups are not only different in the presence of detergent but also in their exposure to sunlight, as the detergent-treated pots are placed in the sun, while the non-detergent pots are in the shade. This introduces another variable (sunlight) that can affect plant growth, making it impossible to attribute any growth differences exclusively to the detergent.
For Gary's experiment, the variable being tested was the effect of sunlight on plant growth. Gary controlled for other possible variables such as the size of the pot, the amount and type of plant food, and the amount of water, to make sure that the only difference between the plants was the amount of sunlight they received.