Answer:
The plots with no fertilizer
Step-by-step explanation:
In an experiment, the control group is used as a comparison for the experimental group (the group being actively changed and observed).
So, in this experiment, the control group is the plots with no fertilizer.
This acts as a good control group because it provides a normal standard to show the effect of fertilizer on the tomato plants.
So, the control group in this experiment are the plots with no fertilizer.