Answer all with full explanation: from (a) to (f). Step by step so i can learn from it

Question 2 How does fertilizer affect the yield of corn? An experimenter prepared three types of fertilizers with varying mixes of potassium and nitrogen peroxide. The first set, A, contained an equal mix of potassium and nitrogen peroxide; the second set, B, contained a one to two mix of potassium and nitrogen peroxide; and the third set, C, contained a two to one mix of potassium and nitrogen peroxide. The experimenter divided a large plot of cultivable land into 150 plots and randomly applied each of the fertilizers to 50 plots and planted them with the same corn type. At the end of the harvest the experimenter recorded the yield of corn in kilograms for each of the plots. (a) Is this an experimental or observational study? In less than 50 words clearly explain your choice based on the extract given above. (b) Define an experimental unit. Give an example of an experimental unit from this question and then state how many experimental units received fertilizer C in the study. (c) For the above study identify, if appropriate, i the response variable(s) ii) the factor ii) the levels of the factor. (d) Are the four principles of experimental design used in this study? Explain in the context of the study. (e) Explain explicitly what a confounding variable is. Identify one plausible confounding variable in this study and explain why it is a confounding variable. (f) What type of experimental design is used in this study? Justify your answer with explanations in the context of the study