The organ system that moves air into, around, and out the body

Skills of homo sapiens were found an excavation. the skulls were preserved because the bodies were frozen. so, these fossils are (blank) fossils. the image shows the evolution of skulls beginning 2 to 3 million years ago. based on the image, modern human skulls(blank) ape skulls.

What is the empirical formula of c6h18o3? ch3o c2h5o c2h6o c2h5o5

At element makes up all organic compounds?