when the triceps brachii extends the arm, the levator

scapulae, rhomboids, and serratus anterior serve as

synergists. speculate on the reason why. (hint: all

the synergist muscles attach the scapula to the axial

skeleton.)

the triceps brachii of the posterior arm is an agonist that causes forearm,this muscle helps depress and protract (pull anteriorly) the scapula and rhomboid minor also works as a synergist to the Pectoralis major in flexing and adducting the arm,the serratus anterior differs from the subclavius and pectoralis minor in that. Functional demands have resulted in the evolution of individual muscles from the basal unit formed by the serratus anterior. In primitive life forms, the main function of the axioscapular group is to control the movements of the vertebral border of the scapula: fibers concerned with the dorsal movement of scapula evolved into the rhomboids, those with ventral motion into serratus anterior, and those with cranial movements into levator scapulae. The evolution of the serratus anterior itself has resulted in (1) grouping of its distal and proximal fibers, (2) size reduction of its intermediate fibers, and (3) the insertion of its dominant superior and inferior parts onto the superior and inferior angles of the scapula

Explanation:

i'd say that the moon rock is about 2.2 billion years old.