Which of the Following Ecosystems Would Likely Have a Larger

Which of the following ecosystems would likely have a larger net primary productivity/hectare and why?

A) open ocean because of the total biomass of photosynthetic autotrophs
B) grassland because of the small standing crop biomass that results from consumption by herbivores and rapid decomposition
C) tropical rain forest because of the massive standing crop biomass and species diversity
D) cave due to the lack of photosynthetic autotrophs
E) tundra because of the incredibly rapid period of growth during the summer season