The question was
Which of the following statements is supported by these data?
A. Phosphorus was the first limiting nutrient followed by nitrogen.
B. Nitrogen was the first limiting nutrient followed by phosphorus.
C. Phosphorus was limiting but nitrogen was not limiting.
D. Nitrogen was limiting but phosphorus was not limiting.
E. Neither nitrogen nor phosphorus was limiting.
The answer was B: Nitrogen is the first limiting nutrient followed by phosphorus, but I do not know why. I thought it would be only phosphorus as the Nitrogen values are always greater than the control values.