Answer:
The correct answer is - there are several other factors that affect the growth of the roots other than fertilizers.
Step-by-step explanation:
Measuring the root mass only is not a correct or accurate way of measuring of the effect of the fertilizers on root growth as it is not the only factor that affect growth of the roots.
The factors that have significant effect on growth of roots of the plant are environmental conditions that are present in the root zone such as gas exchange, Water, Space, Carbohydrates, Non-limiting Temperature, Minerals, Microbial Associations and Low Soil Density.
Thus, the correct answer is - there are several other factors that affect the growth of the roots other than fertilizers.