Final answer:
A tetrapod with scaly skin that lays amniotic eggs is classified as a reptile. Reptiles include animals like crocodiles, lizards, and turtles, which have adaptations like scaly skin and the capacity to lay protected eggs on land.
Step-by-step explanation:
The tetrapod with scaly skin that reproduces by laying an amniotic egg is a reptile.
Tetrapods are a group of animals that have or are descended from species with four limbs. Reptiles are tetrapods and are well adapted to live on land with features such as scaly skin and the ability to lay amniotic eggs. Scaly skin, which prevents water loss, is composed of the protein keratin, a crucial adaptation for terrestrial life.
Amniotic eggs have several membranes and a shell which protect the developing embryo, making it possible for the eggs to be laid on land without drying out. The characteristics given in the question apply to reptiles, which does not include the other options like thecodont, dinosaur, or phytosaur. Among living clades under Reptilia, we have Crocodilia, Sphenodontia, Squamata, and Testudines.