101 4. Which letter of each factor that explains why reptiles became dominant land animals during the Mesozoic era.
a. Reptiles have shell-covered eggs that can be laid on land.
b. Reptiles had an important water-dwelling state (like the tadpole) in their life cycle.
c. Reptiles adapted readily to the drier Mesozoic environment.
d. Reptiles adapted to fill many environmental niches.