**Correct Option: C** ### Explanation of the Correct Answer **C. Synthetic polymers are man-made and typically consist of repeating units of monomers, while biopolymers are naturally occurring macromolecules produced by living organisms.** This statement accurately captures the fundamental distinction between synthetic polymers and biopolymers. Let's break it down: 1. **Synthetic Polymers**: These are materials that are artificially created through chemical processes. They are made by linking together small units called monomers, which are often derived from petroleum or other fossil fuels. Common examples include polyethylene (used in plastic bags), polystyrene (used in foam cups), and nylon (used in clothing). The process of creating synthetic polymers involves polymerization, where monomers are chemically bonded to form long chains. 2. **Biopolymers**: In contrast, biopolymers are naturally occurring macromolecules produced by living organisms. They include proteins, nucleic acids (like DNA and RNA), and polysaccharides (like cellulose and starch). These biopolymers are essential for life and are synthesized through biological processes within cells. For example, proteins are formed by linking amino acids together in specific sequences dictated by genetic information. ### Why Other Options Are Incorrect **A. Synthetic polymers are always biodegradable, while biopolymers are not.** - This statement is misleading. While many synthetic polymers are not biodegradable (e.g., polyethylene), there are some synthetic polymers designed to be biodegradable (e.g., polylactic acid, PLA). Conversely, while many biopolymers are biodegradable (like starch), some, such as certain forms of lignin, can be quite resistant to degradation. Therefore, this option does not accurately reflect the complexities of biodegradability in both categories. **B. Synthetic polymers are derived from natural sources, whereas biopolymers are synthesized in laboratories.** - This statement is incorrect because it reverses the true nature of these materials. Synthetic polymers are primarily derived from non-renewable resources like petroleum, while biopolymers are produced by living organisms. Additionally, biopolymers are not synthesized in laboratories; they are naturally produced by biological processes. **D. Synthetic polymers have a lower molecular weight than biopolymers.** - This statement is also incorrect. Synthetic polymers can have a wide range of molecular weights, often much higher than those of biopolymers. For example, synthetic polymers like polyethylene can have very high molecular weights, while biopolymers like proteins can vary significantly in size. Thus, there is no consistent rule that synthetic polymers have lower molecular weights than biopolymers. ### Summary of Key Points - **Synthetic Polymers**: Man-made, created through polymerization of monomers, often derived from fossil fuels. - **Biopolymers**: Naturally occurring, produced by living organisms, essential for biological functions. - **Biodegradability**: Not a definitive characteristic; some synthetic polymers can be biodegradable, and some biopolymers can resist degradation. - **Molecular Weight**: Varies widely in both categories; no general rule applies. This understanding of synthetic polymers and biopolymers is crucial for grasping their applications, environmental impacts, and roles in both industry and biology.