In subarctic saltmarshes,scientists have found that the addition of calcium has no effect on productivity,but additional iron does increase productivity.In this example,iron
A)is a precursor to calcium.
B)stimulates evapotranspiration.
C)biomagnifies in the marsh plants.
D)is a limiting factor.
E)blocks the effect of calcium.

Question

Quizplus · Accepted Answer

The fact that the addition of iron increases productivity in subarctic saltmarshes indicates that iron is a limiting factor, meaning that it is a nutrient that is scarce and limits the growth of plants in the marshes. The addition of iron alleviates this limitation, allowing for increased productivity.

In Subarctic Saltmarshes,scientists Have Found That the Addition of Calcium