Answer AND Explanation:
gills in adults
-insects, mollusks, crustaceans, amphibians, fishes
scales- amphibians, fishes, reptiles, aves
amniotic eggs
- reptiles, birds, mammals
spinal cord
- vertebrates
ectothermic
- fishes, amphibians, reptiles, and invertebrates
external fertilization - amphibians and fishes, some invertebrates such as coral and sea anemones
lungs in adults
-birds, reptiles, mammals, fishes and amphibians
metamorphosis- amphibians, fishes, insects
