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.
C- all of the solid, rocky parts of the earth
Biosphere is one of the four sub systems of earth. It contains all the living things in the planet. So, plants and animals, as well as microorganisms are part of the biosphere. Humans can also be part of the biosphere according to some scientist, but others put them in another sphere - anthrosphere.
