The graph illustrates how the yield of a wheat crop changes when different amounts of nitrate fertiliser are added. What conclusion can be drawn from the graph?
- ANitrates help the formation of chlorophyll in wheat leaves.
- BThe yield of wheat is proportional to the amount of nitrate fertiliser added.
- CNitrate is needed for the formation of proteins.
- DNitrates are required for healthy plants, but excess nitrates may inhibit growth.