What structure of the respiratory system allows for gas exchange

alveoli
pharynx
nose
trachea

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands

a- multicellular

b-eukaryotic

c-no cell wall

d-heterotrophic

e-autotrophic