f. all of the above
Work Step by Step
Many adaptations allow reptiles to be able to transition from a life totally dependent on water to a life on land where they can exploit more resources that are limited in a watery environment. Reptiles have waterproof skin made of the protein keratin. Members of this group have internal fertilization, which typically happens entirely within the female's body, and they produce amniote eggs where a layer of fluid surrounds the developing embryo, which allows eggs to be laid on land instead of surrounded by water. Reptile kidneys are very efficient, helping these animals conserve water.