The correct option is **B. Natural biopolymers are produced by living organisms, whereas synthetic polymers are chemically engineered.** ### Detailed Explanation: 1. **Understanding Biopolymers and Synthetic Polymers:** - **Natural Biopolymers:** These are large molecules made up of repeating units (monomers) that are produced by living organisms. Examples include proteins (made of amino acids), nucleic acids (DNA and RNA), and polysaccharides (like cellulose and starch). They are formed through biological processes such as protein synthesis and photosynthesis. - **Synthetic Polymers:** These are man-made polymers created through chemical processes. They are typically produced from petrochemicals and include materials like polyethylene, polystyrene, and nylon. The synthesis of these polymers involves various chemical reactions, including polymerization. 2. **Why Option B is Correct:** - The key distinction highlighted in option B is the source of the polymers. Natural biopolymers are inherently linked to biological systems and are synthesized by living organisms, which means they are part of the natural biological processes. In contrast, synthetic polymers are designed and manufactured through human intervention in laboratories or industrial settings. This fundamental difference in origin is crucial in understanding the properties and applications of these materials. 3. **Why the Other Options are Incorrect:** - **Option A:** "Natural biopolymers are always biodegradable, while synthetic polymers are not." - This statement is misleading. While many natural biopolymers are biodegradable due to their biological origin, not all synthetic polymers are non-biodegradable. Some synthetic polymers, like polylactic acid (PLA), are designed to be biodegradable. Therefore, this option overgeneralizes the biodegradability of both types of polymers. - **Option C:** "Natural biopolymers have a uniform molecular weight, while synthetic polymers exhibit a wide range of molecular weights." - This statement is incorrect because natural biopolymers often have a distribution of molecular weights due to variations in their synthesis and the presence of different forms (e.g., different lengths of polysaccharides). Synthetic polymers can also be engineered to have specific molecular weights, but they often exhibit a range of molecular weights due to the nature of the polymerization process. Thus, both types can have a range of molecular weights. - **Option D:** "Natural biopolymers are less complex than synthetic polymers." - This statement is also misleading. Natural biopolymers can be highly complex, with intricate structures and functions (e.g., proteins with specific folding patterns and functions). Synthetic polymers can be designed to be complex as well, but the complexity of a polymer is not solely determined by its origin. Therefore, this option does not accurately reflect the nature of either type of polymer. ### Summary of Key Points: - **Natural biopolymers** are produced by living organisms, while **synthetic polymers** are chemically engineered. - The biodegradability of polymers varies and cannot be generalized based on their origin. - Both natural and synthetic polymers can exhibit a range of molecular weights. - The complexity of polymers is not strictly determined by whether they are natural or synthetic. This understanding of the differences between natural biopolymers and synthetic polymers is essential for grasping their applications, properties, and environmental impacts in chemistry and materials science.