Question

which statement describes how carbon moves through an ecosystem?
a carbon flows from dead organisms to living organisms to the ocean.
b carbon flows from the ocean to the atmosphere to dead organisms.
c carbon flows from the atmosphere to the ocean and then from dead organisms to living organisms.
d carbon flows from the atmosphere to living organisms and then from dead organisms back to the atmosphere.

Explanation:

In an ecosystem, carbon moves through the carbon cycle. Plants take in carbon dioxide ($CO_2$) from the atmosphere during photosynthesis (carbon flows from atmosphere to living organisms). When organisms die, decomposers break them down. Some of the carbon is released back to the atmosphere through processes like decomposition (carbon flows from dead organisms back to the atmosphere).

Answer:

D. Carbon flows from the atmosphere to living organisms and then from dead organisms back to the atmosphere.