Soil condition affects the crop growth directly. If a soil is in fertile condition then the growth of crop which is growing in such soil will be good but if the soil is infertile then the crop will not grow to its fullest. A fertile soil is the one which has optimum condition for growth of a crop like suitable pH, moisture retention capacity, good amount of nutrients & minerals like nitrogen, phosphorus, sodium, potassium, magnesium etc. If a soil is rich in all these constituents then the crop which is growing in this soil will be healthy. But, if a soil is infertile then the crop which is growing on that soil will be under stress and will not be able to grow completely.
The independent variable/answer is what the llama is eating since it changes the dependent variable how fast the llamas run. The independent variable is what is purposely being changed in the experiment.
