Answer:
Fertilizers are the chemicals that are applied on the agricultural crops to increase the yield of crop and protect them from harmful pests. The fertilizers are rich in nitrogen, phosphorus and potassium.
Karen and Jimmy growing tomato to conduct the research. They conclude that large amount of fertilizer is helpful for plant growth. This is wrong because high fertilizer can decrease the plant growth and may cause the death of plant. The fertilizers are required in the exact amount in the plants and there inappropriate level inhibits the plant growth.