The ramus is the smaller of the two main branches. It innervates the and the skin of the back. The ramus is the larger of the two main branches. This splits into multiple other branches, which innervate the , the upper limbs, and the lower limbs. Many of the anterior rami go on to form .

The posterior ramus is the smaller of the two main branches and innervates the deep muscles of the back and the skin of the back. The anterior ramus is the larger of the two main branches and innervates the anterior and lateral portions of the trunk and the upper and lower limbs.

Explanation:

rocks and weathering-matching

he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?