Final answer:
The action performed by the trapezius and pectorals minor muscles that is not performed by the rhomboids and serratus anterior muscles is the elevation of the scapula.
Step-by-step explanation:
The action described that is performed by the trapezius and pectorals minor muscles, but not by the rhomboids and serratus anterior muscles, is the elevation of the scapula. The trapezius muscle attaches to the clavicle, scapula, and spine, and works to elevate, retract and rotate the scapula. In contrast, the rhomboid major and minor pull the scapula medially and are primarily involved in retraction (adduction) of the scapula rather than elevation.
The action described in the question is the movement of the pectoral girdle. The trapezius and pectoralis minor muscles are involved in this movement, while the rhomboids and serratus anterior muscles are not.