Answer:
Physical adaptations do not develop during an individual animal's life, but over many generations. The shape of a bird's beak, the color of a mammal's fur, the thickness or thinness of the fur, the shape of the nose or ears are all examples of physical adaptations which help different animals survive.
I'm pretty sure that it's natural gas.
Nitrogen Fixation: Root and Bacteria Interactions. Nitrogen is an important macronutrient because it is part of nucleic acids and proteins. ... The most important source of BNF is the symbiotic interaction between soil bacteria and legume plants, including many crops important to humans.