Very Short Answer.
Mention two modifications in Reptiles which are required for terrestrial mode of life.
$$\textbf{Explanation:}$$
$$\bullet$$ The two modifications in Reptiles required for terrestrial mode of life are:
$$\text{a)}$$ Presence of Amnion: Reptiles are amniotes that is, they have an extra-embryonic membrane called amnion formed during embryonic development. The amniotic fluid inside the amnion prevents the embryo from drying and also acts as a shock absorber. Thus formation of amnion and presence of amniotic fluid led to less dependence on water for development and allowed amniotes to move to terrestrial habitats.
$$\text{b)}$$ Cleidoic eggs: The eggs in Reptiles have a hard leathery shell, which protect the embryo and permit retention of water and nutrients inside the egg for the developing embryo.