On Earth,all Ecosystems Function Through Two Fundamental Processes,nutrient Cycling and Energy

On Earth,all ecosystems function through two fundamental processes,nutrient cycling and energy flow.Which of the following statements is correct?

A) Nutrient cycling is considered an open process.
B) Energy flow is considered an open process.
C) Both nutrient cycling and energy flow are open processes.
D) Neither nutrient cycling nor energy flow are open processes.
E) Neither nutrient nor energy processes are important for ecosystem functioning.