Steve is most likely using accessory muscles to help him breath. Choose which muscles Steve would be using.
O Diaphragm
O Scalenes
O external intercostals
O Abdominals
O internal intercostals

Muscles for breathing

Explanation:

Muscles which helps in breathing are: diaphragm, scalenes and external intercostals

The predominant muscle of respiration is the diaphragm, as it contracts pleural pressure drops which lowers the alveolar pressure, and draws air in down the pressure gradient from mouth to alveoliExpiration during quiet breathing is predominantly a passive phenomenon, as the respiratory muscles are relaxed and the elastic lung and chest wall return passively to their resting volume, the functional residual capacityThe accessory inspiratory muscles are the sternocleidomastoid, the scalenus anterior, medius, and posterior, the pectoralis major and minor, the inferior fibres of serratus anterior and latissimus dorsi, the serratus posterior anterior which may help in inspiration and also the iliocostalis cervicisTechnically any muscle attached to the upper limb and the thoracic cage can act as an accessory muscle of inspiration through reverse muscle action

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