The correct option is **B. Natural biopolymers are produced by living organisms, while synthetic polymers are chemically engineered and manufactured.** ### 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 play crucial roles in biological processes and are typically biodegradable. - **Synthetic Polymers:** These are man-made polymers created through chemical processes. They are designed and manufactured in laboratories or industrial settings. Common examples include plastics like polyethylene, polystyrene, and nylon. Synthetic polymers can be tailored for specific properties and uses. 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 through metabolic processes in living organisms. In contrast, synthetic polymers are the result of human innovation and chemical engineering, allowing for a wide range of applications and properties that may not exist in nature. 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 oversimplifies the biodegradability aspect. - **Option C:** "Natural biopolymers have a uniform molecular structure, whereas synthetic polymers can have varied structures." - This statement is inaccurate. Natural biopolymers can exhibit a range of structures due to variations in their monomer sequences and modifications (e.g., glycosylation in proteins). Synthetic polymers can also be designed to have uniform structures or varied structures depending on the polymerization process and the types of monomers used. Thus, this option does not accurately reflect the complexity of either category. - **Option D:** "Natural biopolymers are exclusively composed of amino acids, while synthetic polymers can be made from any type of monomer." - This statement is incorrect because it limits natural biopolymers to proteins, which are indeed made of amino acids. However, natural biopolymers also include polysaccharides (made of sugars) and nucleic acids (made of nucleotides). Therefore, this option fails to encompass the full range of natural biopolymers. ### Summary of Key Points: - **Natural biopolymers** are produced by living organisms, while **synthetic polymers** are created through chemical engineering. - Biopolymers include proteins, nucleic acids, and polysaccharides, while synthetic polymers can be made from various monomers. - Not all natural biopolymers are biodegradable, and not all synthetic polymers are non-biodegradable. - Both natural and synthetic polymers can exhibit a variety of structures, depending on their composition and synthesis methods. ### Revision Summary: - Natural biopolymers are produced by living organisms; synthetic polymers are man-made. - Biopolymers include proteins, nucleic acids, and polysaccharides, while synthetic polymers can be diverse. - Biodegradability is not an absolute characteristic of either category. - Both types of polymers can have complex and varied structures.