D.
when revising your professional development plan
The answer is D. learned behavior.
A change in behavior of an organism takes place due an experience is called learning. Animals learn behavior in many ways. On such way is given the question that anole lizard ate bright red butterfly instead small insects which are its normal food and became ill. Anole lizard learned through experience that bright red insects are not its food. Thus, a learned behavior is one that an organism develops by encountering experience.
Nitrogen is special because it is necessary for growth and reproduction. It's needed for plants and animals to survive. The main function for the atmosphere i believe is to give oxygen and nitrogen.
The excretory system allows animals to remove metabolic waste their bodies. Many of these substances are potentially toxic. in Mammals nitrogenous toxins like urea are expelled through liquid urine while in reptiles and birds the nitrogenous compounds are expelled as a solid. This allows birds and reptiles to use less water in the processes of metabolism.