Why is this the answer?

The answer is skeleton because this clever riddle is describing the amazing bone structure that works as the supportive frame inside your body! The riddle uses simple objects we know, like "twigs," "plates," and "spheres," to help us picture the many different shapes of our bones. It is like a secret code that gives clues about the structure that holds you up and lets you move. Let us look closely at the clues in the first line: "Twigs and spheres and poles and plates." The "poles" and "twigs" are great word pictures for the long bones that you have in your body, especially the big ones in your arms and legs. These strong, straight bones are the main supports that allow you to stand up tall, run very fast, and jump high in the air. Next, the riddle mentions "spheres." This refers to the rounded or ball-shaped bones. The best example is your skull, which is a large, hard sphere that acts like a helmet to protect your brain, one of the most important organs you have. Smaller spheres can also describe the rounded ends of bones that meet up at a joint, like your shoulder or hip, allowing you to swing your arms or legs in a circle. Finally, the "plates" refer to the flat bones, such as your ribs, which form a cage, or your shoulder blades. These are like tough, bony plates that shield the soft parts of your body, such as your heart and lungs, from harm. The second part of the riddle is the most important: "Join and bind to reason make." All those differently shaped bones do not float around by themselves. They are all connected, or "joined and bound," at your joints by special, strong tissues. This connecting system is the main "reason" why your body can move. It is what allows your body to have a clear shape and the power to perform every action you choose to do, from writing your name to riding a bicycle. Your skeleton is the wonderful reason your body works!