a layer of water just under a frog's skin captures oxygen from air or water and delivers it to blood vessels at the skin's surface. how might this function relate to the fact that frogs are very sensitive to environmental pollution

Npiranha, fish with large teeth represent the dominant trait. because the dominant trait masks the recessive trait, in a population of 1,000 piranhas, all with large teeth, we could expect about the next generation of fish to have small teeth.