Step-by-step explanation:
The locomotion on land requires more energy than the locomotion in water which can be observed in the land animals like mammals.
In mammals, to move on the land, there should be a well-developed organ which could help in the circulation of blood to all the tissues and the mammals developed the well developed the four-chambered heart which required energy to pump the blood.
The mammals evolved the well-developed lungs to exchange the gases with the environment.