B.)
Weathered rock
I hope this helped
Answer:
List three ways of reducing friction. 1.Polishing the rough surface. 2.Providing all bearings or wheels between the moving parts of a machine or vehicles reduce friction and 3.allow smooth movement as rolling friction is less than sliding friction.
Answer:
Sternocleidomastoid, pectoralis minor, scalenes
Explanation:
During normal inhalation, contraction of the diaphragm and the contraction of external intercostals expands the chest cavity. The increased volume of the thoracic cavity results in reduced alveolar pressure than the atmospheric pressure to facilitate the flow of air into the lungs in response to the pressure gradient.
During deep inhalation as it occurs when running up the stairs, the accessory muscles of inhalation also participate to increase the volume of the chest cavity. The contraction of scalene and sternocleidomastoid muscles increase the volume of the chest cavity further to create a greater drop in alveolar pressure.
During forceful inhalation, the sternocleidomastoid muscles serve to elevate the sternum, the scalene muscles serve to elevate the first two ribs while the pectoralis minor elevate the third through fifth ribs.
