Which of the following features was necessary for adaptation by reptiles to life on land?

A) hard, horny scales
B) internal fertilization by means of a penis
C) shelled egg
D) well-developed lungs
E) All the answer choices describe features necessary for reptile adaptation to life on land.

All of the features listed were necessary for adaptation by reptiles to life on land. Hard, horny scales helped to prevent dehydration and protect against predators, internal fertilization by means of a penis allowed for reproduction to occur on land rather than in water, the shelled egg allowed for the embryo to develop outside of the water, and well-developed lungs allowed for respiration on land.