During inhalation in mammals, the intercostal muscles, specifically the external intercostal muscles, contract, causing the rib cage to expand and move outward, which increases the volume of the thoracic cavity and facilitates air intake; the ribs are raised and move outwards, expanding the chest cavity to allow air to rush into the lungs. 

Also, during inhalation in mammals, the pressure within the thoracic cavity decreases as the volume of the cavity increases. This pressure change, driven by the contraction of the diaphragm and intercostal muscles, causes air to rush into the lungs. 

During inhalation in mammals, the diaphragm contracts and flattens, moving downwards, rather than being raised, to increase the volume of the chest cavity and facilitate air intake. 

Among the given options, the only statement that is incorrect states that during inhalation in mammals, diaphragm is raised instead of stating that it contacts and flattens in order to increasethe volume of chest cavity as well as facilitating the intake of air. Thus, option B  is the correct answer.