Answer:
The carbon atom used to build carbohydrate molacules come from carbon dioxide, the gas that animals exhale with each breath. The Calvin cycle is the term of used for the reaction of photosynthesis that use the energy stored by the light dependent the reaction ot form glucose and other carbohydrate molacules.
Lets say the plant that formed nodules is Species A, and the one who didn't is Species B.
If the nitrogen is concentrated in one area but at a low concentration, then Species A may have formed nodules because it is closer to the concentrated nitrogen. Species B didn't because the nitrogen that is active is being taken by Species A.
One "fact" that is false about testosterone, is that some believe women do not need testosterone as part of their hormones. Alas, women do require testosterone, as without it, can cause numerous dilemmas with their health. For instance, a gain in body fat.
