To determine which statement is true, one would need to analyze the specific data shown in the graph. However, based on the usual context of carbon balance in ecosystems:
If the graph indicates equal amounts of carbon entering and exiting the environment/atmosphere, then the correct statement would be: "The ecosystem is balanced because equal amounts of carbon is entering and exiting the environment/atmosphere."
If the graph shows that more carbon is leaving than entering, the correct statement would be: "The ecosystem is not balanced because more carbon is leaving the atmosphere than being absorbed by the atmosphere."
Conversely, if more carbon is entering than leaving, the statement would be: "The ecosystem is not balanced because more carbon is entering the atmosphere than being absorbed by the environment."
Without the specific graph data, I can't definitively select one statement. You would need to refer to the actual graph you are analyzing to pick the correct response.