What NORMAL process do organisms go through after they die, instead of being fossilized?

Why is the branching pattern of the bronchioles important for the function of the lower respiratory system? a) it keeps foreign particles out of the lungs. b) it maximizes the number of places where oxygen can be transferred into the blood c) it allows the lungs to expand and contract in order to maximize the amount of air that is breathed in d) it keeps the inside of the lungs lubricated