Fish, , reptiles, birds, and mammals have similar .
They all start with gill slits. Fish and some amphibians grow to have gills. Some amphibians, reptiles, birds, and mammals develop lungs to to breathe air. They all start with tails Fish, some amphibians, reptiles, and birds grow tails. Humans do not keep their tails. Fish and reptiles scales. , birds, and humans have skin. Birds have feathers, and have hair
With which animal do humans exhibit the most linear relationship? (point)
O fish
O amphibians
O birds
O reptiles