Cephalization is an evolutionary mechanism which led to the concentration of nerve ganglia, sense organs and mouth at animal's front end giving rise to a head region. Clustering of nerve ganglia in head produced the brain region.
It is a trend adopted in more advanced organisms due to movement and bilateral symmetry. Three groups of animals show cephalization: arthropods (insects), cephalopod molluscs (octopus, squid) and vertebrates (mammals, birds, fishes). Cephalization has been studied extensively in vertebrates. As the groups advance in vertebrates, the brain becomes more elaborate and complex.
Vesicles transport newly synthesized proteins to the Golgi apparatus. After the Golgi apparatus modifies the proteins, vesicles transport the modified proteins to the cell membrane, where they are released.
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.
