Answer:
Bit by bit. They could not move fully to land until plants did it first. We can see intermediate forms like lungfish and mudskippers. Amphibians came next. They only need water for their eggs and tadpoles, and some have avoided that too. The amniotic egg, developed by the first reptiles, made it possible to colonize the land away from water. Arthropods and mollusks followed their own, similar sequence of steps.
Explanation:
