Answer:
body size
more
circulatory system
egg deposition
Step-by-step explanation:
Because of their large body size , ancestral amphibians likely faced challenges supporting themselves out of the aquatic environment.
Although there was far more oxygen available to gills in air than in water, the delicate structure of gills couldn't be supported in the terrestrial environment.
The costs of locomotion on land and greater oxygen demand from enlarged muscles led to modifications of the heart and circulatory system
These early amphibians could not venture too far away from water because egg deposition was restricted to moist environments.