Final answer:
Very young children's throws are primarily composed of arm action, as their coordination and integration of other body parts like legs and torso develop later.
Step-by-step explanation:
Very young children's throws tend to consist of primarily arm action. At an early age, the coordination between different parts of the body is not fully developed, and young children often rely on their arms independently of their legs or torso to perform a throwing motion. This happens because, developmentally, arm control tends to develop before they can effectively use their whole body in a coordinated way. As they grow and their motor skills improve, children learn to integrate leg, torso, and arm actions to produce more effective and powerful throws.