Question

francine is developing a model of the carbon cycle, which involves the movement of carbon among various earth systems. she begins by drawing the diagram shown below. her friend byron evaluates the model, and suggests that she thicken the arrow leading from fossil fuels to the atmosphere. his reasoning is that fossil fuels are being burned at a much faster rate than natural processes are restoring them. how does francines model show the effect of photosynthesis and cellular respiration on earth systems? the model shows that their combined effects determine the amount of solid carbon compounds in the geosphere. the model shows that their combined effects determine the level of carbon dioxide that dissolves in the hydrosphere. the model shows that they have identical effects on carbon dioxide levels in the atmosphere. the model shows that they have opposite effects on carbon dioxide levels in the atmosphere.

Explanation:

Photosynthesis takes in carbon - dioxide from the atmosphere to make organic compounds, reducing atmospheric CO₂ levels. Cellular respiration releases carbon - dioxide back into the atmosphere by breaking down organic compounds, increasing atmospheric CO₂ levels. So, they have opposite effects on carbon - dioxide levels in the atmosphere as shown in the model.

Answer:

The model shows that they have opposite effects on carbon dioxide levels in the atmosphere.