Why is this the answer?

The answer is books because this clever riddle uses fun word pictures to talk about what happens when you read and how much you can learn. It is a puzzle that describes an everyday object as if it were a person, making us think about an ordinary thing in a brand new way. Let us look at the first clue: "Turns us on our backs, and open up our stomachs." This is a tricky way to describe the way you pick up and open a book. Imagine a book is resting on your desk or a bookshelf. When it is lying down flat, its back is where the binding or spine is, the part that holds all the pages together. When you pick up the book to start reading, you are often turning it over to hold it in your hands. Then, when you flip open the cover to get to the pages with the words and stories, that is like "opening up our stomachs." The book's pages are filled with all its content, just like a stomach is filled with food, and when you open the book, the contents are shared with you. The second part of the riddle is about the powerful gift that books give you: "You will be the wisest of men though at start a lummox." A "lummox" is a funny word that means someone who is a bit clumsy or maybe does not know very much about a topic yet. When you first start learning about something new, you might feel uncertain or like you have a lot to discover. But books are like magical keys to knowledge. They are packed with incredible information, exciting adventures, facts about the world, and important lessons. Every story you read and every piece of information you take in helps your brain grow stronger and smarter. The riddle is saying that even if you start out feeling like you do not know anything, reading books will help you grow wiser and wiser over time. A book is a special friend that shares all its wisdom with you just by letting you open its pages.