The trachea, bronchi and bronchioles form the tracheobronchial tree â a system of airways that allow passage of air into the lungs, where gas exchange occurs.he trachea marks the beginning of the tracheobronchial tree. It arises at the lower border of cricoid cartilage in the neck, as a continuation of the larynx. By Bibi Saint-Pol [CC BY-SA 3.0], via Wikimedia Commons. Fig 1.0 â Overview of the tracheobronchial tree.
While relative masses are nice if you want to compare protons, neutrons and electrons to one another, it doesn't tell you what the actual masses of these particles are. In kilograms, the masses are: Neutron = 1.6749286*10-27 kg.
So, we ignore the mass of electron and state that the entire atomic mass of an atom resides in its nucleus, which constitutes of protons and neutrons. therefore, mass number= mass of total neutrons present in the atom + mass of total protons present in the atom 125 = x(1) + 50(1) ( as no. of protons= 50) x= 125-50 x=75