Natural polymers are large molecules made up of repeating units called monomers, which are found in nature. Examples include cellulose, a key component of plant cell walls, and proteins, which are essential for the structure and function of living organisms. These polymers play crucial roles in biological processes and can be derived from various sources, including plants, animals, and microorganisms. Natural polymers are biodegradable, meaning they can break down naturally in the environment, making them more sustainable than many synthetic alternatives. Other examples include starch, used as an energy source in plants, and chitin, found in the exoskeletons of insects and crustaceans. Their unique properties make them valuable in various applications, from food to medicine.