Trees do not emit greenhouse gases. Rather, they are the natural resource that helps clean it out. However, due to deforestation, there aren't enough to combat the amount of gas that is produced at the current rate.
One reason could be that there are a high number of predators killing rabbits in large quantities. Another is there may not be enough vegetation for the rabbits. They may also have a different animal competing for the same kinds of plants they eat.
The answer you my friend are looking for is D
The answer is glucose.
Hope this helps.