Francine's 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. If Francine adopts Byron's suggestion, how could her model be used to explain a significant change to earths systems?

According to the model, photosynthesis and cellular respiration are decreasing Carbon Dioxide levels in the atmosphere whilst the combustion of fossil fuels is increasing it.

Explanation:

According to the model, forest fires and the combustion of fossil fuels

such as coal, oil and natural gas work together to increase the volume of carbon emissions in the atmosphere.

The model shows that though Photosynthesis (which involves the use of sunlight and carbon dioxide by plants to produce food) is reducing the amount of carbon dioxide in the air, there is still an imbalance to favour of the later.

Ironically, the forests which help to clean up the carbon dioxide is being burnt down.

Cheers

1. a tropical dry forest carries out more rapid nutrient cycling

small, big, or no change could occur in the phenotype. it could cause something as simple as a cats ears to curl backwards or something as frighting as death. it could also occur in the protien-coding area and have an effect on that but no effect on the amino acids. what has to occur is a changing in the hox gene or the control gene.