What is the main difference for movement in the aquatic and terrestrial environment.

What is the main difference for movement in the aquatic and terrestrial environment. how to distinguish by their appearance actively moving inhabitants of these living environments?

When moving in a terrestrial environment, there is little interference. The inhabitants of this environment have adapted to be mobile and make many movements with different parts of the body. So primates, for example, have arms and legs that help them to move and work. Residents of the aquatic environment faced a problem, interference during movement. The bodies of the sea creatures have been modified to make the minimum amount of movement. They have neither arms nor legs, fins are what helps them to move. Unlike terrestrial inhabitants, aquatic ones seem to soar in the sky, showing grace in the water.