Listed below are four adaptations of terrestrial vertebrates. which is a characteristic only of truly terrestrial animals with no need to return to water at any stage of the life cycle

This question is incomplete as options are not provided. However, the correct answer is 'amniotic eggs'. Amniotes are tetrapod vertebrates that include reptiles, birds, and mammals. Amniotes differ from aquatic organisms such as fish in that the mother retains the fertilised egg and lays the egg on land. This is in contrast to fish that spawn unfertilised eggs within the water, after which the male released sperm into the water to facilitate fertilisation. The eggs of amniotes are protected by membranes. In humans, these membranes include the amniotic sac.

Hmmm i'm not sure about this one