In mammals, the process of inspiration involves           a. alveolar collapse.   b. negative pressure generated in the chest, causing the lungs to expand to fill the vacuum.   c. the ribs and diaphragm pulling on the lungs to produce expansion.   d. multiple functions within the bronchial tree

Correct B). Negative pressure generated in the chest, causing the lungs to expand to fill the vacuum

The process of inhalation occurred due to the increased volume of the lung in which there is the contraction of diaphragm and expansion of the chest wall. It creates a negative pressure, which results in a decreased pressure in comparison to the atmosphere. Thus air goes into the lung.  

Hence, the correct answer would be option B.

thats not even an aswer choice