What is one way in which energy flow differs from chemical cycling?
A)Energy flow is unidirectional; chemical elements can be recycled.
B)Energy can enter but cannot leave an ecosystem; chemical elements can leave but cannot enter an ecosystem.
C)Energy flows from lower to higher trophic levels; chemicals cycle from higher to lower trophic levels.
D)Energy can both enter and leave an ecosystem; chemical elements always remain within a single ecosystem.

Question

Quizplus · Accepted Answer

Energy flows through an ecosystem in one direction, from the sun to autotrophs to heterotrophs, and ultimately dissipates as heat. Chemical elements, on the other hand, can be recycled by different organisms and environmental processes. For example, carbon dioxide released by respiration can be taken up by plants during photosynthesis to create new organic molecules, and then be consumed by herbivores and decomposers, ultimately returning to the atmosphere as carbon dioxide.

What Is One Way in Which Energy Flow Differs from Chemical