The Low Productivity of Arctic Tundra Ecosystems Results

Multiple Choice

The low productivity of arctic tundra ecosystems results

A) entirely because tundra has low evapotranspiration.
B) entirely because tundra soils are low in nutrients.
C) entirely because tundra soils retain water poorly.
D) because tundra soils have low nutrients and retain water poorly.
E) because tundra has low evapotranspiration and low-nutrient soils.