Final answer:
Reptiles and birds have an amniotic egg, which allows development in a terrestrial environment.
Step-by-step explanation:
Reptiles and Birds have an amniotic egg. Unlike amphibians, reptiles and birds produce amniotic eggs that have a shell and extra-embryonic membranes to protect and nourish the embryo. The amniotic egg allows development to occur in a terrestrial environment, making reptiles and birds less dependent on water for reproduction. Amphibians, on the other hand, lay eggs in water because their eggs lack a waterproof covering.