AP BIOLOGY

Detailed explanation-1: -Frogs, toads, newts, and salamanders are the best-known members of this smallest class of vertebrates. They all share several other characteristics. Most have thin, moist skin that is smooth and soft. They do not have scales or claws, although the skin of a toad is dry and covered with bumps.

Detailed explanation-2: -Frogs, toads, and salamanders are amphibians. Many of these species must keep their skin moist by periodically returning to wet areas. All of them must return to water in order to reproduce because their eggs would dry out otherwise. They start life with gills, like fish, and later develop lungs to breathe air.

Detailed explanation-3: -Summary. Amphibians reproduce sexually with either external or internal fertilization. Amphibians may attract mates with calls or scents. Amphibians do not produce amniotic eggs, so they must reproduce in water.

Detailed explanation-4: -This fringe leaf froglet is an amphibian, its skin moist with mucus.

Detailed explanation-5: -Amphibians are a class of cold-blooded vertebrates made up of frogs, toads, salamanders, newts, and caecilians (wormlike animals with poorly developed eyes).