You are having lunch with an elderly friend when suddenly he begins to experience chest pain and tightness. He reaches into his pocket, gets out one of his nitroglycerin tablets and quickly takes it. After the episode passes, your friend asks you how the nitroglycerin helps his angina. You explain that nitroglycerin gets converted by cells to nitric oxide (NO) causing the smooth muscle cells of the blood vessel to relax and increase blood flow to the heart.
He pushes you for a more detailed explanation, so you explain further that .

The generation of nitric oxide is done by almost every kind of cell present in the human body, it is one of the essential constituents that plays an important function in maintaining proper health of blood vessels. The nitric oxide acts as a vasodilator, that is, it relaxes the blood vessels' inner muscles, thus making the blood vessels to broaden.  

Therefore it can be concluded that nitric oxide enhances the flow of blood and thus reduces the blood pressure. In this manner, nitric oxide helps in tackling the symptoms of conditions like angina.  

At the molecular level. the activation of guanylyl cyclase is done by nitric oxide, which further catalyzes the production of cGMP. This cGMP further functions as an intracellular messenger in a pathway that results in the relaxation of the smooth muscles.  

lets get this bread mom

the correct answer is option b

behavioral response need communication and thus co-ordination at several levels such as interaction among cells, organ system and the entire organism.

behavioral response produces both internal and environmental stimulus.