What is genetic engineering, and what are the basic steps involved in it?

the correct answer is that the hypothesis was not supported, as the data suggest that too much fertilizer can prevent the growth of the plant.  

it was noticed that the plants that did not get any fertilizer seem to grow less in comparison to the plants that did receive a moderate amount of fertilizer, however, the plants that were receiving a much greater amount of fertilizer did not perform as anticipated as they were not growing better and bigger in comparison to the others.  

this shows that the plants exhibit some kind of requirements, and if that requirement is surpassed, then the plants do not get enough benefit, in certain cases, it can even cause them much harm.