A corn farmer is interested in reducing the number of days it takes for his corn to silk. He has decided to set up a controlled experiment that manipulates the nominal variable “fertilizer,” having two categories: 1 = limestone and 2 = nitrogen. Another nominal variable is “soil type,” with two categories: 1 = silt and 2 = peat.

Two experimental fields were each planted with corn. Fertilizer was added to the first field but not to the second. The first field produced 250 bushels of corn per acre and the second field produced 180 bushels of corn per acre. Since nothing else but water was added to either fields, the higher yield in the first field must be due to the fertilizer.Which of the following, if true, most seriously weakens the argument above?radio_button_uncheckedA small amount of the fertilizer leached into the second field.radio_button_uncheckedFour different types of corn grown in equal proportions in each of the fields.radio_button_uncheckedSome weeds that compete with corn cannot tolerate high amounts of fertilizer in the soil.radio_button_uncheckedThe two experimental fields were located in different states.

An experiment has to be made through which the effects of five different varieties of fertilizers on the yield of a certain crop. Which design can be adopted?Choose one optionC.R. DesignR.B. DesignL.S. DesignFactorial designs

in an experiment investigating the effects of different types of fertilizer on plant growth, what is the independent variable? a. The plant growth b. The duration of the experiment c. The environmental conditions d. The type of fertilizer used

, you will give the three groups of GM corn plants different amounts of water.As a class, identify variables or factors that you will need to keep the same between the three groups to ensure a fair test.

When experimenting with the growth of a plant, a scientist uses three of the same type of plants, two different fertilizers, equal light, and equal water. What type of variable is the water?a.Control variableb.Interdependent variablec.Independent variabled.Dependent variable