Here's why:
* Carbohydrates are made from carbon, hydrogen, and oxygen. Animals can obtain these elements from their food, but they lack the necessary enzymes to assemble them into complex carbohydrate molecules.
* Animals rely on plants for carbohydrates. Plants are able to photosynthesize, meaning they use sunlight to convert carbon dioxide and water into glucose (a simple sugar), which is the building block for all other carbohydrates.
* Animals break down carbohydrates for energy. Animals consume plant-based carbohydrates and break them down into simpler sugars that their bodies can use for energy.
Therefore, while animals can convert some carbohydrates from one form to another, they cannot create new carbohydrate molecules from basic elements.